Low distortion sinewave oscillator without big capacitor.

E

Edward Rawde 1 year ago

Not long ago JM posted a 1KHz sinewave oscillator with very low distortion. It used a 470uF non polarized capacitor which in practice would probably be made from two 1000uF capacitors. There's nothing wrong with that but I wanted to see whether I could make a working circuit without needing such a large capacitor.

What I have so far is below.

Any comments? What's the best way to control the output level? Currently it's 5v pk-pk but I rather have half that.

Version 4.1 SHEET 1 3020 2548 WIRE 80 -208 -288 -208 WIRE 800 -208 160 -208 WIRE -288 -96 -288 -208 WIRE 80 -96 -288 -96 WIRE 400 -96 160 -96 WIRE -288 32 -288 -96 WIRE -176 32 -288 32 WIRE -32 32 -96 32 WIRE 48 32 -32 32 WIRE 208 32 128 32 WIRE 256 32 208 32 WIRE 400 32 400 -96 WIRE 400 32 320 32 WIRE 464 32 400 32 WIRE 608 32 544 32 WIRE 656 32 608 32 WIRE 800 32 800 -208 WIRE 800 32 720 32 WIRE -752 48 -816 48 WIRE -624 48 -688 48 WIRE -288 144 -288 32 WIRE -176 144 -288 144 WIRE 208 144 208 32 WIRE 256 144 208 144 WIRE 608 144 608 32 WIRE 656 144 608 144 WIRE -816 160 -816 48 WIRE -752 160 -816 160 WIRE -624 160 -624 48 WIRE -624 160 -672 160 WIRE -32 160 -32 32 WIRE -32 160 -112 160 WIRE 400 160 400 32 WIRE 400 160 320 160 WIRE 800 160 800 32 WIRE 800 160 720 160 WIRE 832 160 800 160 WIRE -176 176 -288 176 WIRE 256 176 224 176 WIRE 656 176 624 176 WIRE 224 208 224 176 WIRE 624 208 624 176 WIRE -1968 224 -1968 144 WIRE -1008 272 -1104 272 WIRE -816 272 -816 160 WIRE -816 272 -944 272 WIRE -736 272 -816 272 WIRE -624 288 -624 160 WIRE -624 288 -672 288 WIRE -544 288 -624 288 WIRE -416 288 -480 288 WIRE -288 288 -288 176 WIRE -288 288 -336 288 WIRE -208 288 -288 288 WIRE 208 288 -128 288 WIRE 400 288 400 160 WIRE 400 288 208 288 WIRE -736 304 -816 304 WIRE -816 336 -816 304 WIRE 400 336 400 288 WIRE -1968 400 -1968 304 WIRE -1856 400 -1968 400 WIRE -1664 400 -1776 400 WIRE 208 400 208 288 WIRE 208 400 -1600 400 WIRE 400 448 400 416 WIRE 544 448 400 448 WIRE 368 464 336 464 WIRE -1968 496 -1968 400 WIRE -1968 496 -2304 496 WIRE 368 496 368 464 WIRE 400 496 400 448 WIRE 544 496 544 448 WIRE -2432 544 -2432 496 WIRE -2304 560 -2304 496 WIRE -2240 560 -2304 560 WIRE -2144 560 -2176 560 WIRE 384 608 384 560 WIRE 544 608 544 576 WIRE 544 608 384 608 WIRE -1968 640 -1968 496 WIRE -32 656 -32 160 WIRE 208 656 208 400 WIRE 384 656 384 608 WIRE 800 656 800 160 WIRE -2304 672 -2304 560 WIRE -2256 672 -2304 672 WIRE -2144 688 -2144 560 WIRE -2144 688 -2192 688 WIRE -2032 688 -2144 688 WIRE -2432 704 -2432 624 WIRE -2256 704 -2432 704 WIRE -2432 736 -2432 704 WIRE -2432 736 -2544 736 WIRE -32 752 -32 720 WIRE 208 752 208 720 WIRE 384 752 384 720 WIRE 800 752 800 720 WIRE -2544 768 -2544 736 WIRE -2432 768 -2432 736 WIRE -1968 800 -1968 736 WIRE -2544 864 -2544 832 WIRE -32 880 -32 832 WIRE 208 880 208 832 WIRE 208 880 -32 880 WIRE 384 880 384 832 WIRE 384 880 208 880 WIRE 800 880 800 832 WIRE 800 880 384 880 WIRE -2432 912 -2432 848 WIRE -32 976 -32 880 WIRE -320 992 -416 992 WIRE -160 992 -256 992 WIRE -416 1072 -416 992 WIRE -368 1072 -416 1072 WIRE -256 1072 -304 1072 WIRE -160 1072 -160 992 WIRE -160 1072 -176 1072 WIRE -1360 1136 -1360 1040 WIRE -2160 1152 -2160 1040 WIRE -1664 1152 -1664 1040 WIRE -160 1184 -160 1072 WIRE -160 1184 -240 1184 WIRE -32 1184 -32 1056 WIRE -32 1184 -160 1184 WIRE 48 1184 -32 1184 WIRE 176 1184 128 1184 WIRE -1968 1200 -1968 880 WIRE -1968 1200 -2096 1200 WIRE -1904 1200 -1968 1200 WIRE -1728 1200 -1904 1200 WIRE -416 1200 -416 1072 WIRE -416 1200 -768 1200 WIRE -304 1200 -416 1200 WIRE -208 1216 -240 1216 WIRE -1664 1296 -1664 1248 WIRE -1360 1296 -1360 1216 WIRE -1104 1296 -1104 272 WIRE -1104 1296 -1360 1296 WIRE -208 1328 -208 1216 WIRE -1360 1376 -1360 1296 WIRE -1904 1408 -1904 1200 WIRE -1664 1424 -1664 1376 WIRE -1424 1424 -1664 1424 WIRE -2160 1456 -2160 1248 WIRE -1968 1456 -2160 1456 WIRE -1904 1584 -1904 1504 WIRE -1360 1584 -1360 1472 WIRE -2160 1664 -2160 1456 WIRE -1328 1744 -1456 1744 WIRE -1248 1744 -1328 1744 WIRE -1056 1744 -1168 1744 WIRE -1664 1792 -1664 1424 WIRE -1328 1792 -1328 1744 WIRE -1056 1792 -1056 1744 WIRE -1456 1840 -1456 1744 WIRE -1456 1840 -1600 1840 WIRE -1392 1840 -1456 1840 WIRE -2544 1952 -2544 1920 WIRE -2544 1952 -2592 1952 WIRE -2592 1968 -2592 1952 WIRE -1664 1968 -1664 1888 WIRE -1328 1968 -1328 1888 WIRE -2544 1984 -2544 1952 WIRE -1824 2112 -1952 2112 WIRE -1648 2112 -1824 2112 WIRE -768 2112 -768 1200 WIRE -768 2112 -1568 2112 WIRE -2160 2160 -2160 1744 WIRE -1824 2160 -1824 2112 WIRE -1952 2208 -1952 2112 WIRE -1952 2208 -2096 2208 WIRE -1888 2208 -1952 2208 WIRE -2160 2336 -2160 2256 WIRE -1824 2336 -1824 2256 FLAG 224 208 0 FLAG 624 208 0 FLAG 832 160 vout FLAG -272 1168 vcc FLAG -272 1232 vee FLAG -2592 1968 0 FLAG -2544 1840 vcc FLAG -2544 2064 vee FLAG -144 128 vcc FLAG -144 192 vee FLAG 288 128 vcc FLAG 288 192 vee FLAG 688 128 vcc FLAG 688 192 vee FLAG 336 464 0 FLAG 416 528 vcc FLAG 352 528 vee FLAG -2224 656 vcc FLAG -1968 144 vcc FLAG -2224 720 vee FLAG -1360 1040 vcc FLAG -1824 2336 vee FLAG -2160 2336 vee FLAG -2432 496 vcc FLAG -2432 912 0 FLAG -1360 1584 0 FLAG -704 256 vcc FLAG -704 320 vee FLAG -816 336 0 FLAG 240 1184 vcc FLAG -1328 1968 vee FLAG -1664 1968 vee FLAG -1056 1792 0 FLAG -1904 1584 0 FLAG -1664 1040 vcc FLAG -2160 1040 vcc FLAG -208 1328 0 FLAG -2544 864 0 SYMBOL res -80 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 10K SYMBOL res 144 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 16K SYMBOL res 560 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 16K SYMBOL cap 320 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 10n SYMBOL cap 720 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 10n SYMBOL res 176 -224 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 10K SYMBOL res 176 -80 M270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R5 SYMATTR Value 82k SYMBOL cap -256 976 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C3 SYMATTR Value 1000n SYMBOL res 32 1200 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R10 SYMATTR Value 330K SYMBOL diode 240 1168 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName D1 SYMATTR Value 1N914 SYMBOL res -48 960 R0 SYMATTR InstName R11 SYMATTR Value 40.2K SYMBOL res 560 592 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R18 SYMATTR Value 10K SYMBOL res 416 432 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R19 SYMATTR Value 10k SYMBOL diode -48 720 M180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D2 SYMATTR Value 1N914 SYMBOL diode 192 720 M180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D12 SYMATTR Value 1N914 SYMBOL diode 400 720 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D13 SYMATTR Value 1N914 SYMBOL diode 784 720 M180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D14 SYMATTR Value 1N914 SYMBOL res -48 736 R0 SYMATTR InstName R13 SYMATTR Value 68k SYMBOL res 192 736 R0 SYMATTR InstName R14 SYMATTR Value 68k SYMBOL res 400 736 M0 SYMATTR InstName R15 SYMATTR Value 68k SYMBOL res 784 736 R0 SYMATTR InstName R16 SYMATTR Value 68k SYMBOL voltage -2544 1824 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V3 SYMATTR Value 15 SYMBOL voltage -2544 1968 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V4 SYMATTR Value 15 SYMBOL OpAmps\\LT1679 -144 160 R0 SYMATTR InstName U5 SYMBOL OpAmps\\LT1679 288 160 R0 SYMATTR InstName U6 SYMBOL OpAmps\\LT1679 688 160 R0 SYMATTR InstName U8 SYMBOL res -112 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R8 SYMATTR Value 10k SYMBOL res -320 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value 560 SYMBOL cap -480 272 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C8 SYMATTR Value 1000n SYMBOL res -272 1088 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R6 SYMATTR Value 47k SYMBOL cap -304 1056 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C4 SYMATTR Value 10000n SYMBOL OpAmps\\LT1679 384 528 R90 WINDOW 3 37 22 VRight 2 SYMATTR InstName U1 SYMBOL pnp -2032 736 M180 WINDOW 3 84 0 Left 2 SYMATTR Value 2N3906 SYMATTR InstName Q5 SYMBOL res -1984 208 R0 SYMATTR InstName R12 SYMATTR Value 56k SYMBOL res -1760 384 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R25 SYMATTR Value 2.7Meg SYMBOL cap -2176 544 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C7 SYMATTR Value 10p SYMBOL res -1984 784 R0 SYMATTR InstName R27 SYMATTR Value 1 SYMBOL npn -2096 1152 M0 SYMATTR InstName Q6 SYMATTR Value MAT-02 SYMBOL npn -1728 1152 R0 SYMATTR InstName Q7 SYMATTR Value MAT-02 SYMBOL npn -1424 1376 R0 SYMATTR InstName Q8 SYMATTR Value MAT-02 SYMBOL npn -1968 1408 R0 SYMATTR InstName Q9 SYMATTR Value MAT-02 SYMBOL res -1552 2096 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R28 SYMATTR Value 120k SYMBOL res -1376 1120 R0 SYMATTR InstName R29 SYMATTR Value 100k SYMBOL res -1680 1280 R0 SYMATTR InstName R30 SYMATTR Value 1 SYMBOL npn -1888 2160 R0 SYMATTR InstName Q11 SYMATTR Value MAT-02 SYMBOL npn -2096 2160 M0 SYMATTR InstName Q12 SYMATTR Value MAT-02 SYMBOL res -2176 1648 R0 SYMATTR InstName R31 SYMATTR Value 1 SYMBOL res -2448 528 R0 SYMATTR InstName R32 SYMATTR Value 10k SYMBOL res -2448 752 R0 SYMATTR InstName R33 SYMATTR Value 15k SYMBOL cap -944 256 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C12 SYMATTR Value 1000n SYMBOL res -656 144 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R7 SYMATTR Value 14k SYMBOL cap -688 32 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C5 SYMATTR Value 10p SYMBOL cap -1600 384 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C6 SYMATTR Value 100n SYMBOL npn -1392 1792 R0 SYMATTR InstName Q1 SYMATTR Value MAT-02 SYMBOL npn -1600 1792 M0 SYMATTR InstName Q2 SYMATTR Value MAT-02 SYMBOL res -1152 1728 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R17 SYMATTR Value 120k SYMBOL OpAmps\\LT1679 -704 288 R0 SYMATTR InstName U2 SYMBOL OpAmps\\LT1679 -272 1200 M0 SYMATTR InstName U3 SYMBOL OpAmps\\LT1679 -2224 688 R0 SYMATTR InstName U4 SYMBOL cap -2560 768 R0 SYMATTR InstName C9 SYMATTR Value 10n TEXT -2792 1560 Left 2 !.tran 0 10 0 1u startup TEXT -2792 1504 Left 2 !.options plotwinsize=0 numdgt=15 TEXT -2248 -112 Left 2 ;Low distortion 1KHz oscillator. Edward Rawde 30 March 2025.\nBased on designs by JM and BS.

Vote

B

Bill Sloman 1 year ago

It relies on the Analog Devices MAT-02 dual transistor, which is now obsolete

formatting link

The .asc file shows eight NPN transistors labelled MAT-02, presumably in four pairs of the part, but it isn't clear which of the eight transistors should be paired up.

The rectified currents from the four phased shifted versions of of the output waveform flow through R13, R14, R15 and R16 into R11 and through it into the virtual earth set up at the inverting input of U3, where the summed current is compared with a fixed current drawn from the +15V rail through D1 and R10.

Doubling R10 from 330k to 680k would roughly halve the output amplitude. One could be more precise, but it wouudl be hard to justify the extra effort.

Vote

E

Edward Rawde 1 year ago

"Bill Sloman" snipped-for-privacy@ieee.org wrote in message news:vsdi3h$3nagd$ snipped-for-privacy@dont-email.me...

BCM61B is available and very reasonably priced.

formatting link

can be used for Q1 Q2 and Q3 Q4 in the circuit below.

The remaining four transistors can use MAT14

formatting link

although a bit pricey has four independent matched transistors. I can't find an LTSpice model for MAT14 so MAT02 is still shown in the circuit below.

Ah yes, that takes care of the output level. The revised circuit is below. Line 459 will need to be unwrapped.

Version 4.1 SHEET 1 3020 2792 WIRE 80 -208 -288 -208 WIRE 800 -208 160 -208 WIRE -288 -96 -288 -208 WIRE 80 -96 -288 -96 WIRE 400 -96 160 -96 WIRE -288 32 -288 -96 WIRE -176 32 -288 32 WIRE -32 32 -96 32 WIRE 48 32 -32 32 WIRE 208 32 128 32 WIRE 256 32 208 32 WIRE 400 32 400 -96 WIRE 400 32 320 32 WIRE 464 32 400 32 WIRE 608 32 544 32 WIRE 656 32 608 32 WIRE 800 32 800 -208 WIRE 800 32 720 32 WIRE -752 48 -816 48 WIRE -624 48 -688 48 WIRE -288 144 -288 32 WIRE -176 144 -288 144 WIRE 208 144 208 32 WIRE 256 144 208 144 WIRE 608 144 608 32 WIRE 656 144 608 144 WIRE 800 144 800 32 WIRE 928 144 800 144 WIRE 1072 144 992 144 WIRE 1168 144 1072 144 WIRE 1216 144 1168 144 WIRE -816 160 -816 48 WIRE -752 160 -816 160 WIRE -624 160 -624 48 WIRE -624 160 -672 160 WIRE -32 160 -32 32 WIRE -32 160 -112 160 WIRE 400 160 400 32 WIRE 400 160 320 160 WIRE 800 160 800 144 WIRE 800 160 720 160 WIRE -176 176 -288 176 WIRE 256 176 224 176 WIRE 656 176 624 176 WIRE 224 208 224 176 WIRE 624 208 624 176 WIRE -1968 224 -1968 144 WIRE -1008 272 -1104 272 WIRE -816 272 -816 160 WIRE -816 272 -944 272 WIRE -736 272 -816 272 WIRE 1072 272 1072 144 WIRE -624 288 -624 160 WIRE -624 288 -672 288 WIRE -544 288 -624 288 WIRE -416 288 -480 288 WIRE -288 288 -288 176 WIRE -288 288 -336 288 WIRE -208 288 -288 288 WIRE 208 288 -128 288 WIRE 400 288 400 160 WIRE 400 288 208 288 WIRE -736 304 -816 304 WIRE -816 336 -816 304 WIRE 400 336 400 288 WIRE -1968 400 -1968 304 WIRE -1856 400 -1968 400 WIRE -1664 400 -1776 400 WIRE 208 400 208 288 WIRE 208 400 -1600 400 WIRE 1072 416 1072 352 WIRE 400 448 400 416 WIRE 544 448 400 448 WIRE 368 464 336 464 WIRE -1968 496 -1968 400 WIRE -1968 496 -2304 496 WIRE 368 496 368 464 WIRE 400 496 400 448 WIRE 544 496 544 448 WIRE -2432 544 -2432 496 WIRE -2304 560 -2304 496 WIRE -2240 560 -2304 560 WIRE -2144 560 -2176 560 WIRE 384 608 384 560 WIRE 544 608 544 576 WIRE 544 608 384 608 WIRE -1968 640 -1968 496 WIRE -32 656 -32 160 WIRE 208 656 208 400 WIRE 384 656 384 608 WIRE 800 656 800 160 WIRE -2304 672 -2304 560 WIRE -2256 672 -2304 672 WIRE -2144 688 -2144 560 WIRE -2144 688 -2192 688 WIRE -2032 688 -2144 688 WIRE -2432 704 -2432 624 WIRE -2256 704 -2432 704 WIRE -2432 736 -2432 704 WIRE -2432 736 -2544 736 WIRE -32 752 -32 720 WIRE 208 752 208 720 WIRE 384 752 384 720 WIRE 800 752 800 720 WIRE -2544 768 -2544 736 WIRE -2432 768 -2432 736 WIRE -2544 864 -2544 832 WIRE -32 880 -32 832 WIRE 208 880 208 832 WIRE 208 880 -32 880 WIRE 384 880 384 832 WIRE 384 880 208 880 WIRE 800 880 800 832 WIRE 800 880 384 880 WIRE -2432 912 -2432 848 WIRE -32 976 -32 880 WIRE -320 992 -416 992 WIRE -160 992 -256 992 WIRE -416 1072 -416 992 WIRE -368 1072 -416 1072 WIRE -256 1072 -304 1072 WIRE -160 1072 -160 992 WIRE -160 1072 -176 1072 WIRE -1360 1136 -1360 1040 WIRE -2160 1152 -2160 1040 WIRE -1664 1152 -1664 1040 WIRE -160 1184 -160 1072 WIRE -160 1184 -240 1184 WIRE -32 1184 -32 1056 WIRE -32 1184 -160 1184 WIRE 48 1184 -32 1184 WIRE 176 1184 128 1184 WIRE -1968 1200 -1968 736 WIRE -1968 1200 -2096 1200 WIRE -1904 1200 -1968 1200 WIRE -1728 1200 -1904 1200 WIRE -416 1200 -416 1072 WIRE -416 1200 -768 1200 WIRE -304 1200 -416 1200 WIRE -208 1216 -240 1216 WIRE -1360 1296 -1360 1216 WIRE -1104 1296 -1104 272 WIRE -1104 1296 -1360 1296 WIRE -208 1328 -208 1216 WIRE -1904 1408 -1904 1200 WIRE -1360 1408 -1360 1296 WIRE -2160 1456 -2160 1248 WIRE -1968 1456 -2160 1456 WIRE -1664 1456 -1664 1248 WIRE -1424 1456 -1664 1456 WIRE -1360 1584 -1360 1504 WIRE -1904 1648 -1904 1504 WIRE -1328 1744 -1456 1744 WIRE -1232 1744 -1328 1744 WIRE -1088 1744 -1152 1744 WIRE -1664 1792 -1664 1456 WIRE -1328 1792 -1328 1744 WIRE -1088 1808 -1088 1744 WIRE -1456 1840 -1456 1744 WIRE -1456 1840 -1600 1840 WIRE -1392 1840 -1456 1840 WIRE -2544 1952 -2544 1920 WIRE -2544 1952 -2592 1952 WIRE -2592 1968 -2592 1952 WIRE -1664 1968 -1664 1888 WIRE -1328 1968 -1328 1888 WIRE -2544 1984 -2544 1952 WIRE -1824 2128 -1952 2128 WIRE -1648 2128 -1824 2128 WIRE -768 2128 -768 1200 WIRE -768 2128 -1568 2128 WIRE -2160 2176 -2160 1456 WIRE -1824 2176 -1824 2128 WIRE -1952 2224 -1952 2128 WIRE -1952 2224 -2096 2224 WIRE -1888 2224 -1952 2224 WIRE -2160 2352 -2160 2272 WIRE -1824 2352 -1824 2272 FLAG 224 208 0 FLAG 624 208 0 FLAG -272 1168 vcc FLAG -272 1232 vee FLAG -2592 1968 0 FLAG -2544 1840 vcc FLAG -2544 2064 vee FLAG -144 128 vcc FLAG -144 192 vee FLAG 288 128 vcc FLAG 288 192 vee FLAG 688 128 vcc FLAG 688 192 vee FLAG 336 464 0 FLAG 416 528 vcc FLAG 352 528 vee FLAG -2224 656 vcc FLAG -1968 144 vcc FLAG -2224 720 vee FLAG -1360 1040 vcc FLAG -1824 2352 vee FLAG -2160 2352 vee FLAG -2432 496 vcc FLAG -2432 912 0 FLAG -1360 1584 0 FLAG -704 256 vcc FLAG -704 320 vee FLAG -816 336 0 FLAG 240 1184 vcc FLAG -1664 1040 vcc FLAG -2160 1040 vcc FLAG -208 1328 0 FLAG -2544 864 0 FLAG 1168 144 output FLAG -1904 1648 0 FLAG -1328 1968 vee FLAG -1664 1968 vee FLAG -1088 1808 0 FLAG 1072 416 0 SYMBOL res -80 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 10K SYMBOL res 144 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 16K SYMBOL res 560 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 16K SYMBOL cap 320 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 10n SYMBOL cap 720 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 10n SYMBOL res 176 -224 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 10K SYMBOL res 176 -80 M270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R5 SYMATTR Value 82k SYMBOL cap -256 976 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C3 SYMATTR Value 1000n SYMBOL res 32 1200 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R10 SYMATTR Value 820k SYMBOL diode 240 1168 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName D1 SYMATTR Value 1N914 SYMBOL res -48 960 R0 SYMATTR InstName R11 SYMATTR Value 47k SYMBOL res 560 592 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R18 SYMATTR Value 10K SYMBOL res 416 432 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R19 SYMATTR Value 10k SYMBOL diode -48 720 M180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D2 SYMATTR Value 1N914 SYMBOL diode 192 720 M180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D12 SYMATTR Value 1N914 SYMBOL diode 400 720 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D13 SYMATTR Value 1N914 SYMBOL diode 784 720 M180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D14 SYMATTR Value 1N914 SYMBOL res -48 736 R0 SYMATTR InstName R13 SYMATTR Value 68k SYMBOL res 192 736 R0 SYMATTR InstName R14 SYMATTR Value 68k SYMBOL res 400 736 M0 SYMATTR InstName R15 SYMATTR Value 68k SYMBOL res 784 736 R0 SYMATTR InstName R16 SYMATTR Value 68k SYMBOL voltage -2544 1824 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V3 SYMATTR Value 15 SYMBOL voltage -2544 1968 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V4 SYMATTR Value 15 SYMBOL OpAmps\\LT1679 -144 160 R0 SYMATTR InstName U5 SYMBOL OpAmps\\LT1679 288 160 R0 SYMATTR InstName U6 SYMBOL OpAmps\\LT1679 688 160 R0 SYMATTR InstName U8 SYMBOL res -112 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R8 SYMATTR Value 10k SYMBOL res -320 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value 560 SYMBOL cap -480 272 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C8 SYMATTR Value 1000n SYMBOL res -272 1088 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R6 SYMATTR Value 47k SYMBOL cap -304 1056 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C4 SYMATTR Value 10000n SYMBOL OpAmps\\LT1679 384 528 R90 WINDOW 3 37 22 VRight 2 SYMATTR InstName U1 SYMBOL pnp -2032 736 M180 WINDOW 3 84 0 Left 2 SYMATTR Value 2N3906 SYMATTR InstName Q9 SYMBOL res -1984 208 R0 SYMATTR InstName R12 SYMATTR Value 56k SYMBOL res -1760 384 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R25 SYMATTR Value 2.7Meg SYMBOL cap -2176 544 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C7 SYMATTR Value 10p SYMBOL npn -2096 1152 M0 SYMATTR InstName Q5 SYMATTR Value MAT-02 SYMBOL npn -1728 1152 R0 SYMATTR InstName Q7 SYMATTR Value MAT-02 SYMBOL npn -1424 1408 R0 SYMATTR InstName Q8 SYMATTR Value MAT-02 SYMBOL npn -1968 1408 R0 SYMATTR InstName Q6 SYMATTR Value MAT-02 SYMBOL res -1552 2112 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R28 SYMATTR Value 120k SYMBOL res -1376 1120 R0 SYMATTR InstName R29 SYMATTR Value 100k SYMBOL res -2448 528 R0 SYMATTR InstName R32 SYMATTR Value 10k SYMBOL res -2448 752 R0 SYMATTR InstName R33 SYMATTR Value 15k SYMBOL cap -944 256 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C12 SYMATTR Value 1000n SYMBOL res -656 144 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R7 SYMATTR Value 14k SYMBOL cap -688 32 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C5 SYMATTR Value 10p SYMBOL cap -1600 384 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C6 SYMATTR Value 100n SYMBOL OpAmps\\LT1679 -704 288 R0 SYMATTR InstName U2 SYMBOL OpAmps\\LT1679 -272 1200 M0 SYMATTR InstName U3 SYMBOL OpAmps\\LT1679 -2224 688 R0 SYMATTR InstName U4 SYMBOL cap -2560 768 R0 SYMATTR InstName C9 SYMATTR Value 10n SYMBOL cap 992 128 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C10 SYMATTR Value 10000n SYMBOL npn -2096 2176 M0 SYMATTR InstName Q1 SYMATTR Value BCM61B SYMBOL npn -1888 2176 R0 SYMATTR InstName Q2 SYMATTR Value BCM61B SYMBOL npn -1600 1792 M0 SYMATTR InstName Q3 SYMATTR Value BCM61B SYMBOL npn -1392 1792 R0 SYMATTR InstName Q4 SYMATTR Value BCM61B SYMBOL res -1136 1728 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R17 SYMATTR Value 120k SYMBOL res 1056 256 R0 SYMATTR InstName R21 SYMATTR Value 100k TEXT -2792 1560 Left 2 !.tran 0 10 0 1u startup TEXT -2792 1504 Left 2 !.options plotwinsize=0 numdgt=15 TEXT -2248 -112 Left 3 ;Low distortion 1KHz oscillator. Edward Rawde 31 March 2025.\nBased on designs by JM and BS. TEXT -576 1368 Left 2 !.MODEL BCM61B NPN\n+ IS = 1.822E-14\n+ NF = 0.9932\n+ ISE = 2.894E-16\n+ NE = 1.4\n+ BF = 324.4\n+ IKF =

0.109\n+ VAF = 82\n+ NR = 0.9931\n+ ISC = 9.982E-12\n+ NC = 1.763\n+ BR = 8.29\n+ IKR = 0.09\n+ VAR = 17.9\n+ RB = 10\n+ IRB = 5E-06\n+ RBM = 5\n+ RE = 0.649\n+ RC = 0.7014\n+ CJE = 1.244E-11\n+ VJE = 0.7579\n+ MJE = 0.3656\n+ TF = 4.908E-10\n+ XTF = 9.51\n+ VTF = 2.927\n+ ITF = 0.3131\n+ PTF = 0\n+ CJC = 3.347E-12\n+ VJC = 0.5463\n+ MJC = 0.391\n+ XCJC = 0.6193\n+ TR = 9E-08\n+ CJS = 0\n+ VJS = 0.75\n+ MJS = 0.333\n+ XTB = 0\n+ XTI = 3\n+ EG = 1.11\n+ FC = 0.979 TEXT -2656 1256 Left 3 ;Use MAT14 for Q5-Q8

Vote

B

Bill Sloman 1 year ago

Not all that well. Using the positive rail as your voltage reference suck, and including the diode drops of the rectifying diodes is even worse.There are precision rectifiers that use op amps to take out the diode drop, and synchromous rectifiers built around transmission gates can be even more precise.

I did that, and the circuit does work, after a fashion.

It still uses eight transistors to do what John May did with three separate discrete transistors.

Because he didn't use a matched pair, he had to use two 250R emitter resistors to get the operating conditions he needed to make them act as parts of a three-transistor asymmetric Wilson current mirror.

formatting link

He then had to by-pass the resistors with a big capacitor to get the effect he needed. This introduced a phase shift, but John May's phase-shift oscillator offers four different phases from which he could pick off the right phase to get the correction signal he needed.

By summing current from two adjacent phases you can get exactly the phase shift you need, but he didn't to be all that exact.

Using a matched pair for the two transistors at the bottom of the mirror you can get rid of one of the emitter resistors and make the other one small enough not to matter (so you don't need the capacitor), but you do need to pick off a different phase to get the right feedback.

The MAT04 is totally unnecessary.

Or it least that's the way it strikes me. I've yet to get a simulation to work to illustrate the point - it's a complicated circuit, and once it hits saturation the subtle effects that stabilise it get swamped.

I need a better grasp of what's going on in the circuit, and a way to start it up that doesn't let it slide over into saturation before it stabilises.

Vote

E

Edward Rawde 1 year ago

Ok thanks for taking the time to look at it. Let me know when you get it to work.

Vote

J

JM 1 year ago

You'd be as well omitting Q1, Q2, Q11 and Q12. Just tie R17 to Q7e(Q8b) with other end to vee, and R28 to Q6e(Q9b) (adjust polarity of gain vontrol voltage). There will be no loss in performance. Q6-9 are within an overall control loop, and there is no need for matched transistors (wthin reason).

If you splash out on a matched quad it would be better used to construct a four quadrant multiplier, it would have lower harmonics than this circuit if done correctly.

Are the one ohm resistors used for some sort of simulation/measurement purpose?

Vote

I

invalid unparseable 1 year ago

Suppose you built an oscillator and had a switch that varied the loop gain between 0.98 and 1.02. Now measure the amplitude of N cycles and flip the switch if it's too high or too low. Switch at the zero crossing.

I wonder what distortion would be like.

(I wouldn't really do that. It's just an idea to play with.)

Vote

B

Bill Sloman 1 year ago

<snip>

I made those changes to Edward Rawde's original circuit, and the revised circuit worked. I haven't yet got a clue how, but poking around in a working simulation should let me work out what's actually going on. It's

4.10am my time and I should have gone to bed four hours ago, so I'll leave that until tomorrow.

I can comfort myself with the idea that my reservations about the number of transistors in the original circuit turned out to be well founded, but John May clearly grasped how the circuit worked, and I've yet to get there.

Vote

B

Bill Sloman 1 year ago

Why not measure it? LTSpice could probably give you a sine wave whose amplitude ramped up linearly for a bit, and ramped back down again.

Do a DFT on that and you'd have your answer. It wouldn't be good.

Only if you don't know what you are talking about.

Vote

J

john larkin 1 year ago

An idea is like a cute baby puppy. Some people want to feed it and play with it and some people want to club it to death.

Vote

E

Edward Rawde 1 year ago

"JM" snipped-for-privacy@gmail.com wrote in message news: snipped-for-privacy@4ax.com...

...

I can get it to work wthout Q1 and Q2 as you suggested. But I can't get it to work without Q11, Q12. I reversed all five diodes and connected D1 to vee.

The one ohm resistors are so I can see the current in LTSpice. It may be better to use a lower value such as 0.001 ohm.

Version 4.1 SHEET 1 3020 2548 WIRE 80 -208 -288 -208 WIRE 800 -208 160 -208 WIRE -288 -96 -288 -208 WIRE 80 -96 -288 -96 WIRE 400 -96 160 -96 WIRE -288 32 -288 -96 WIRE -176 32 -288 32 WIRE -32 32 -96 32 WIRE 48 32 -32 32 WIRE 208 32 128 32 WIRE 256 32 208 32 WIRE 400 32 400 -96 WIRE 400 32 320 32 WIRE 464 32 400 32 WIRE 608 32 544 32 WIRE 656 32 608 32 WIRE 800 32 800 -208 WIRE 800 32 720 32 WIRE -752 48 -816 48 WIRE -624 48 -688 48 WIRE -288 144 -288 32 WIRE -176 144 -288 144 WIRE 208 144 208 32 WIRE 256 144 208 144 WIRE 608 144 608 32 WIRE 656 144 608 144 WIRE -816 160 -816 48 WIRE -752 160 -816 160 WIRE -624 160 -624 48 WIRE -624 160 -672 160 WIRE -32 160 -32 32 WIRE -32 160 -112 160 WIRE 400 160 400 32 WIRE 400 160 320 160 WIRE 800 160 800 32 WIRE 800 160 720 160 WIRE 832 160 800 160 WIRE -176 176 -288 176 WIRE 256 176 224 176 WIRE 656 176 624 176 WIRE 224 208 224 176 WIRE 624 208 624 176 WIRE -1968 224 -1968 144 WIRE -1008 272 -1104 272 WIRE -816 272 -816 160 WIRE -816 272 -944 272 WIRE -736 272 -816 272 WIRE -624 288 -624 160 WIRE -624 288 -672 288 WIRE -544 288 -624 288 WIRE -416 288 -480 288 WIRE -288 288 -288 176 WIRE -288 288 -336 288 WIRE -208 288 -288 288 WIRE 208 288 -128 288 WIRE 400 288 400 160 WIRE 400 288 208 288 WIRE -736 304 -816 304 WIRE -816 336 -816 304 WIRE 400 336 400 288 WIRE -1968 400 -1968 304 WIRE -1856 400 -1968 400 WIRE -1664 400 -1776 400 WIRE 208 400 208 288 WIRE 208 400 -1600 400 WIRE 400 448 400 416 WIRE 544 448 400 448 WIRE 368 464 336 464 WIRE -1968 496 -1968 400 WIRE -1968 496 -2304 496 WIRE 368 496 368 464 WIRE 400 496 400 448 WIRE 544 496 544 448 WIRE -2432 544 -2432 496 WIRE -2304 560 -2304 496 WIRE -2240 560 -2304 560 WIRE -2144 560 -2176 560 WIRE 384 608 384 560 WIRE 544 608 544 576 WIRE 544 608 384 608 WIRE -1968 640 -1968 496 WIRE -32 656 -32 160 WIRE 208 656 208 400 WIRE 384 656 384 608 WIRE 800 656 800 160 WIRE -2304 672 -2304 560 WIRE -2256 672 -2304 672 WIRE -2144 688 -2144 560 WIRE -2144 688 -2192 688 WIRE -2032 688 -2144 688 WIRE -2432 704 -2432 624 WIRE -2256 704 -2432 704 WIRE -2432 736 -2432 704 WIRE -2432 736 -2544 736 WIRE -32 752 -32 720 WIRE 208 752 208 720 WIRE 384 752 384 720 WIRE 800 752 800 720 WIRE -2544 768 -2544 736 WIRE -2432 768 -2432 736 WIRE -1968 800 -1968 736 WIRE -2544 864 -2544 832 WIRE -32 880 -32 832 WIRE 208 880 208 832 WIRE 208 880 -32 880 WIRE 384 880 384 832 WIRE 384 880 208 880 WIRE 800 880 800 832 WIRE 800 880 384 880 WIRE -2432 912 -2432 848 WIRE -32 976 -32 880 WIRE -320 992 -416 992 WIRE -160 992 -256 992 WIRE -416 1072 -416 992 WIRE -368 1072 -416 1072 WIRE -256 1072 -304 1072 WIRE -160 1072 -160 992 WIRE -160 1072 -176 1072 WIRE -1360 1136 -1360 1040 WIRE -2160 1152 -2160 1040 WIRE -1664 1152 -1664 1040 WIRE -160 1184 -160 1072 WIRE -160 1184 -240 1184 WIRE -32 1184 -32 1056 WIRE -32 1184 -160 1184 WIRE 48 1184 -32 1184 WIRE 176 1184 128 1184 WIRE -1968 1200 -1968 880 WIRE -1968 1200 -2096 1200 WIRE -1904 1200 -1968 1200 WIRE -1728 1200 -1904 1200 WIRE -416 1200 -416 1072 WIRE -416 1200 -768 1200 WIRE -304 1200 -416 1200 WIRE -208 1216 -240 1216 WIRE -1664 1296 -1664 1248 WIRE -1360 1296 -1360 1216 WIRE -1104 1296 -1104 272 WIRE -1104 1296 -1360 1296 WIRE -208 1328 -208 1216 WIRE -1360 1376 -1360 1296 WIRE -1904 1408 -1904 1200 WIRE -1664 1424 -1664 1376 WIRE -1424 1424 -1664 1424 WIRE -2160 1456 -2160 1248 WIRE -1968 1456 -2160 1456 WIRE -1664 1552 -1664 1424 WIRE -1904 1584 -1904 1504 WIRE -1360 1584 -1360 1472 WIRE -2160 1664 -2160 1456 WIRE -1664 1728 -1664 1632 WIRE -2544 1952 -2544 1920 WIRE -2544 1952 -2592 1952 WIRE -2592 1968 -2592 1952 WIRE -2544 1984 -2544 1952 WIRE -1824 2112 -1952 2112 WIRE -1648 2112 -1824 2112 WIRE -768 2112 -768 1200 WIRE -768 2112 -1568 2112 WIRE -2160 2160 -2160 1744 WIRE -1824 2160 -1824 2112 WIRE -1952 2208 -1952 2112 WIRE -1952 2208 -2096 2208 WIRE -1888 2208 -1952 2208 WIRE -2160 2336 -2160 2256 WIRE -1824 2336 -1824 2256 FLAG 224 208 0 FLAG 624 208 0 FLAG 832 160 vout FLAG -272 1168 vcc FLAG -272 1232 vee FLAG -2592 1968 0 FLAG -2544 1840 vcc FLAG -2544 2064 vee FLAG -144 128 vcc FLAG -144 192 vee FLAG 288 128 vcc FLAG 288 192 vee FLAG 688 128 vcc FLAG 688 192 vee FLAG 336 464 0 FLAG 416 528 vcc FLAG 352 528 vee FLAG -2224 656 vcc FLAG -1968 144 vcc FLAG -2224 720 vee FLAG -1360 1040 vcc FLAG -1824 2336 vee FLAG -2160 2336 vee FLAG -2432 496 vcc FLAG -2432 912 0 FLAG -1360 1584 0 FLAG -704 256 vcc FLAG -704 320 vee FLAG -816 336 0 FLAG 240 1184 vcc FLAG -1904 1584 0 FLAG -1664 1040 vcc FLAG -2160 1040 vcc FLAG -208 1328 0 FLAG -2544 864 0 FLAG -1664 1728 vee SYMBOL res -80 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 10K SYMBOL res 144 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 16K SYMBOL res 560 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 16K SYMBOL cap 320 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 10n SYMBOL cap 720 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 10n SYMBOL res 176 -224 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 10K SYMBOL res 176 -80 M270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R5 SYMATTR Value 82k SYMBOL cap -256 976 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C3 SYMATTR Value 1000n SYMBOL res 32 1200 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R10 SYMATTR Value 330K SYMBOL diode 240 1168 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName D1 SYMATTR Value 1N914 SYMBOL res -48 960 R0 SYMATTR InstName R11 SYMATTR Value 40.2K SYMBOL res 560 592 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R18 SYMATTR Value 10K SYMBOL res 416 432 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R19 SYMATTR Value 10k SYMBOL diode -48 720 M180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D2 SYMATTR Value 1N914 SYMBOL diode 192 720 M180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D12 SYMATTR Value 1N914 SYMBOL diode 400 720 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D13 SYMATTR Value 1N914 SYMBOL diode 784 720 M180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D14 SYMATTR Value 1N914 SYMBOL res -48 736 R0 SYMATTR InstName R13 SYMATTR Value 68k SYMBOL res 192 736 R0 SYMATTR InstName R14 SYMATTR Value 68k SYMBOL res 400 736 M0 SYMATTR InstName R15 SYMATTR Value 68k SYMBOL res 784 736 R0 SYMATTR InstName R16 SYMATTR Value 68k SYMBOL voltage -2544 1824 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V3 SYMATTR Value 15 SYMBOL voltage -2544 1968 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V4 SYMATTR Value 15 SYMBOL OpAmps\\LT1679 -144 160 R0 SYMATTR InstName U5 SYMBOL OpAmps\\LT1679 288 160 R0 SYMATTR InstName U6 SYMBOL OpAmps\\LT1679 688 160 R0 SYMATTR InstName U8 SYMBOL res -112 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R8 SYMATTR Value 10k SYMBOL res -320 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value 560 SYMBOL cap -480 272 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C8 SYMATTR Value 1000n SYMBOL res -272 1088 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R6 SYMATTR Value 47k SYMBOL cap -304 1056 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C4 SYMATTR Value 10000n SYMBOL OpAmps\\LT1679 384 528 R90 WINDOW 3 37 22 VRight 2 SYMATTR InstName U1 SYMBOL pnp -2032 736 M180 WINDOW 3 84 0 Left 2 SYMATTR Value 2N3906 SYMATTR InstName Q5 SYMBOL res -1984 208 R0 SYMATTR InstName R12 SYMATTR Value 56k SYMBOL res -1760 384 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R25 SYMATTR Value 2.7Meg SYMBOL cap -2176 544 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C7 SYMATTR Value 10p SYMBOL res -1984 784 R0 SYMATTR InstName R27 SYMATTR Value 1 SYMBOL npn -2096 1152 M0 SYMATTR InstName Q6 SYMATTR Value MAT-02 SYMBOL npn -1728 1152 R0 SYMATTR InstName Q7 SYMATTR Value MAT-02 SYMBOL npn -1424 1376 R0 SYMATTR InstName Q8 SYMATTR Value MAT-02 SYMBOL npn -1968 1408 R0 SYMATTR InstName Q9 SYMATTR Value MAT-02 SYMBOL res -1552 2096 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R28 SYMATTR Value 120k SYMBOL res -1376 1120 R0 SYMATTR InstName R29 SYMATTR Value 100k SYMBOL res -1680 1280 R0 SYMATTR InstName R30 SYMATTR Value 1 SYMBOL npn -1888 2160 R0 SYMATTR InstName Q11 SYMATTR Value MAT-02 SYMBOL npn -2096 2160 M0 SYMATTR InstName Q12 SYMATTR Value MAT-02 SYMBOL res -2176 1648 R0 SYMATTR InstName R31 SYMATTR Value 1 SYMBOL res -2448 528 R0 SYMATTR InstName R32 SYMATTR Value 10k SYMBOL res -2448 752 R0 SYMATTR InstName R33 SYMATTR Value 15k SYMBOL cap -944 256 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C12 SYMATTR Value 1000n SYMBOL res -656 144 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R7 SYMATTR Value 14k SYMBOL cap -688 32 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C5 SYMATTR Value 10p SYMBOL cap -1600 384 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C6 SYMATTR Value 100n SYMBOL res -1648 1648 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R17 SYMATTR Value 120k SYMBOL OpAmps\\LT1679 -704 288 R0 SYMATTR InstName U2 SYMBOL OpAmps\\LT1679 -272 1200 M0 SYMATTR InstName U3 SYMBOL OpAmps\\LT1679 -2224 688 R0 SYMATTR InstName U4 SYMBOL cap -2560 768 R0 SYMATTR InstName C9 SYMATTR Value 10n TEXT -2792 1560 Left 2 !.tran 0 10 0 1u startup TEXT -2792 1504 Left 2 !.options plotwinsize=0 numdgt=15 TEXT -2248 -112 Left 2 ;Low distortion 1KHz oscillator. Edward Rawde 30 March 2025.\nBased on designs by JM and BS.

Vote

J

JM 1 year ago

Clicking on a pin shows the current flowing in the pin.

You will need to adjust the feedback to suit. Start with a -5 or -6 gain block after the integrator and adjust it's gain until the startup is clean (no saturation).

Vote

B

Bill Sloman 1 year ago

Some ideas are more like blood-sucking parasites.

This one isn't great.

What you are talking about is sine wave with a slow triangular wave amplitude modulation.

If you wanted a sine wave with a slow sinusoidal amplitude modulation you'd add a small wave of almost the same frequency - so for a 1kHz sine wave you'd add a little bit of a 1.001Hz sine wave.

For a triangular amplitude modulatulion you'd need to add progressively smaller increments of progressively higher (or lower) frequency, properly phased, 1.001kHz, 1.003kHz, 1.005Khz etc.

If your switch acted infinitely fast, you'd have no upper limit on the higher-frequency components you'd generate.

Do try to think about what you are posting before you post it.

Vote

B

Bill Sloman 1 year ago

On 4/04/2025 11:33 am, JM wrote:

Here's my version of John May's variation.

Version 4 SHEET 1 3020 2548 WIRE 80 -208 -288 -208 WIRE 800 -208 160 -208 WIRE -288 -96 -288 -208 WIRE 80 -96 -288 -96 WIRE 400 -96 160 -96 WIRE -288 32 -288 -96 WIRE -176 32 -288 32 WIRE -32 32 -96 32 WIRE 48 32 -32 32 WIRE 208 32 128 32 WIRE 256 32 208 32 WIRE 400 32 400 -96 WIRE 400 32 320 32 WIRE 464 32 400 32 WIRE 608 32 544 32 WIRE 656 32 608 32 WIRE 800 32 800 -208 WIRE 800 32 720 32 WIRE -752 48 -816 48 WIRE -624 48 -688 48 WIRE -288 144 -288 32 WIRE -176 144 -288 144 WIRE 208 144 208 32 WIRE 256 144 208 144 WIRE 608 144 608 32 WIRE 656 144 608 144 WIRE -816 160 -816 48 WIRE -752 160 -816 160 WIRE -624 160 -624 48 WIRE -624 160 -672 160 WIRE -32 160 -32 32 WIRE -32 160 -112 160 WIRE 400 160 400 32 WIRE 400 160 320 160 WIRE 800 160 800 32 WIRE 800 160 720 160 WIRE 832 160 800 160 WIRE -176 176 -288 176 WIRE 256 176 224 176 WIRE 656 176 624 176 WIRE 224 208 224 176 WIRE 624 208 624 176 WIRE -1968 224 -1968 144 WIRE -1008 272 -1104 272 WIRE -816 272 -816 160 WIRE -816 272 -944 272 WIRE -736 272 -816 272 WIRE -624 288 -624 160 WIRE -624 288 -672 288 WIRE -544 288 -624 288 WIRE -416 288 -480 288 WIRE -288 288 -288 176 WIRE -288 288 -336 288 WIRE -208 288 -288 288 WIRE 208 288 -128 288 WIRE 400 288 400 160 WIRE 400 288 208 288 WIRE -736 304 -816 304 WIRE -816 336 -816 304 WIRE 400 336 400 288 WIRE -1968 400 -1968 304 WIRE -1856 400 -1968 400 WIRE -1664 400 -1776 400 WIRE 208 400 208 288 WIRE 208 400 -1600 400 WIRE 400 448 400 416 WIRE 544 448 400 448 WIRE 368 464 336 464 WIRE -1968 496 -1968 400 WIRE -1968 496 -2304 496 WIRE 368 496 368 464 WIRE 400 496 400 448 WIRE 544 496 544 448 WIRE -2432 544 -2432 496 WIRE -2304 560 -2304 496 WIRE -2240 560 -2304 560 WIRE -2144 560 -2176 560 WIRE 384 608 384 560 WIRE 544 608 544 576 WIRE 544 608 384 608 WIRE -1968 640 -1968 496 WIRE -32 656 -32 160 WIRE 208 656 208 400 WIRE 384 656 384 608 WIRE 800 656 800 160 WIRE -2304 672 -2304 560 WIRE -2256 672 -2304 672 WIRE -2144 688 -2144 560 WIRE -2144 688 -2192 688 WIRE -2032 688 -2144 688 WIRE -2432 704 -2432 624 WIRE -2256 704 -2432 704 WIRE -2432 736 -2432 704 WIRE -2432 736 -2544 736 WIRE -32 752 -32 720 WIRE 208 752 208 720 WIRE 384 752 384 720 WIRE 800 752 800 720 WIRE -2544 768 -2544 736 WIRE -2432 768 -2432 736 WIRE -1968 800 -1968 736 WIRE -1360 800 -1360 704 WIRE -2544 864 -2544 832 WIRE -32 880 -32 832 WIRE 208 880 208 832 WIRE 208 880 -32 880 WIRE 384 880 384 832 WIRE 384 880 208 880 WIRE 800 880 800 832 WIRE 800 880 384 880 WIRE -2432 912 -2432 848 WIRE -1360 960 -1360 880 WIRE -1104 960 -1104 272 WIRE -1104 960 -1360 960 WIRE -32 976 -32 880 WIRE -320 992 -416 992 WIRE -160 992 -256 992 WIRE -416 1072 -416 992 WIRE -368 1072 -416 1072 WIRE -256 1072 -304 1072 WIRE -160 1072 -160 992 WIRE -160 1072 -176 1072 WIRE -2160 1152 -2160 1040 WIRE -1664 1152 -1664 1040 WIRE -160 1184 -160 1072 WIRE -160 1184 -240 1184 WIRE -32 1184 -32 1056 WIRE -32 1184 -160 1184 WIRE 48 1184 -32 1184 WIRE 176 1184 128 1184 WIRE 320 1184 240 1184 WIRE -1968 1200 -1968 880 WIRE -1968 1200 -2096 1200 WIRE -1904 1200 -1968 1200 WIRE -1728 1200 -1904 1200 WIRE -416 1200 -416 1072 WIRE -416 1200 -1088 1200 WIRE -304 1200 -416 1200 WIRE -2480 1216 -2480 1184 WIRE -2480 1216 -2528 1216 WIRE -208 1216 -240 1216 WIRE -2528 1232 -2528 1216 WIRE -1360 1232 -1360 960 WIRE -2480 1248 -2480 1216 WIRE -1664 1280 -1664 1248 WIRE -1424 1280 -1664 1280 WIRE -208 1328 -208 1216 WIRE -1664 1360 -1664 1280 WIRE -1360 1440 -1360 1328 WIRE -1664 1504 -1664 1440 WIRE -2160 1648 -2160 1248 WIRE -1648 1648 -2160 1648 WIRE -1088 1648 -1088 1200 WIRE -1088 1648 -1568 1648 WIRE -1904 1712 -1904 1200 WIRE -2160 1760 -2160 1648 WIRE -1968 1760 -2160 1760 WIRE -1904 1888 -1904 1808 FLAG 224 208 0 FLAG 624 208 0 FLAG 832 160 vout FLAG -272 1168 vcc FLAG -272 1232 vee FLAG -2528 1232 0 FLAG -2480 1104 vcc FLAG -2480 1328 vee FLAG -144 128 vcc FLAG -144 192 vee FLAG 288 128 vcc FLAG 288 192 vee FLAG 688 128 vcc FLAG 688 192 vee FLAG 336 464 0 FLAG 416 528 vcc FLAG 352 528 vee FLAG -2224 656 vcc FLAG -1968 144 vcc FLAG -2224 720 vee FLAG -1360 704 vcc FLAG -2432 496 vcc FLAG -2432 912 0 FLAG -1360 1440 0 FLAG -704 256 vcc FLAG -704 320 vee FLAG -816 336 0 FLAG -1664 1504 vee FLAG -1904 1888 0 FLAG -1664 1040 vcc FLAG -2160 1040 vcc FLAG -208 1328 0 FLAG -2544 864 0 FLAG 320 1184 vee SYMBOL res -80 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 10K SYMBOL res 144 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 16K SYMBOL res 560 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 16K SYMBOL cap 320 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 10n SYMBOL cap 720 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 10n SYMBOL res 176 -224 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 10K SYMBOL res 176 -80 M270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R5 SYMATTR Value 82k SYMBOL cap -256 976 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C3 SYMATTR Value 1000n SYMBOL res 32 1200 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R10 SYMATTR Value 820K SYMBOL diode 176 1200 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D1 SYMATTR Value 1N914 SYMBOL res -48 960 R0 SYMATTR InstName R11 SYMATTR Value 40.2K SYMBOL res 560 592 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R18 SYMATTR Value 10K SYMBOL res 416 432 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R19 SYMATTR Value 10k SYMBOL diode -16 656 M0 SYMATTR InstName D2 SYMATTR Value 1N914 SYMBOL diode 224 656 M0 SYMATTR InstName D12 SYMATTR Value 1N914 SYMBOL diode 368 656 R0 SYMATTR InstName D13 SYMATTR Value 1N914 SYMBOL diode 816 656 M0 SYMATTR InstName D14 SYMATTR Value 1N914 SYMBOL res -48 736 R0 SYMATTR InstName R13 SYMATTR Value 68k SYMBOL res 192 736 R0 SYMATTR InstName R14 SYMATTR Value 68k SYMBOL res 400 736 M0 SYMATTR InstName R15 SYMATTR Value 68k SYMBOL res 784 736 R0 SYMATTR InstName R16 SYMATTR Value 68k SYMBOL voltage -2480 1088 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V3 SYMATTR Value 15 SYMBOL voltage -2480 1232 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V4 SYMATTR Value 15 SYMBOL OpAmps\\LT1679 -144 160 R0 SYMATTR InstName U5 SYMBOL OpAmps\\LT1679 288 160 R0 SYMATTR InstName U6 SYMBOL OpAmps\\LT1679 688 160 R0 SYMATTR InstName U8 SYMBOL res -112 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R8 SYMATTR Value 10k SYMBOL res -320 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value 560 SYMBOL cap -480 272 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C8 SYMATTR Value 1000n SYMBOL res -272 1088 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R6 SYMATTR Value 82k SYMBOL cap -304 1056 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C4 SYMATTR Value 10000n SYMBOL OpAmps\\LT1679 384 528 R90 WINDOW 3 37 22 VRight 2 SYMATTR InstName U1 SYMBOL pnp -2032 736 M180 WINDOW 3 84 0 Left 2 SYMATTR Value 2N3906 SYMATTR InstName Q5 SYMBOL res -1984 208 R0 SYMATTR InstName R12 SYMATTR Value 56k SYMBOL res -1760 384 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R25 SYMATTR Value 2.7Meg SYMBOL cap -2176 544 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C7 SYMATTR Value 10p SYMBOL res -1984 784 R0 SYMATTR InstName R27 SYMATTR Value 1 SYMBOL npn -2096 1152 M0 SYMATTR InstName Q6 SYMATTR Value 2N3904 SYMBOL npn -1728 1152 R0 SYMATTR InstName Q1B SYMATTR Value BCM61B SYMBOL npn -1424 1232 R0 SYMATTR InstName Q8 SYMATTR Value 2N3904 SYMBOL npn -1968 1712 R0 SYMATTR InstName Q1A SYMATTR Value BCM61B SYMBOL res -1552 1632 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R28 SYMATTR Value 15k SYMBOL res -1376 784 R0 SYMATTR InstName R29 SYMATTR Value 100k SYMBOL res -2448 528 R0 SYMATTR InstName R32 SYMATTR Value 10k SYMBOL res -2448 752 R0 SYMATTR InstName R33 SYMATTR Value 15k SYMBOL cap -944 256 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C12 SYMATTR Value 1000n SYMBOL res -656 144 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R7 SYMATTR Value 14k SYMBOL cap -688 32 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C5 SYMATTR Value 10p SYMBOL cap -1600 384 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C6 SYMATTR Value 100n SYMBOL res -1648 1456 R180 WINDOW 0 31 76 Left 2 WINDOW 3 31 40 Left 2 SYMATTR InstName R17 SYMATTR Value 120k SYMBOL OpAmps\\LT1679 -704 288 R0 SYMATTR InstName U2 SYMBOL OpAmps\\LT1679 -272 1200 M0 SYMATTR InstName U3 SYMBOL OpAmps\\LT1679 -2224 688 R0 SYMATTR InstName U4 SYMBOL cap -2560 768 R0 SYMATTR InstName C9 SYMATTR Value 10n TEXT -2792 1560 Left 2 !.tran 0 10 0 1u startup TEXT -2792 1504 Left 2 !.options plotwinsize=0 numdgt=15 TEXT -2248 -112 Left 2 ;Low distortion 1KHz oscillator. Edward Rawde 30 March 2025.\nBased on designs by JM and BS, and now modified again by Bill Sloman TEXT -2848 128 Left 2 !.MODEL BCM61B NPN\n+ IS = 1.822E-14\n+ NF =

0.9932\n+ ISE = 2.894E-16\n+ NE = 1.4\n+ BF = 324.4\n+ IKF = 0.109\n+ VAF = 82\n+ NR = 0.9931\n+ ISC = 9.982E-12\n+ NC = 1.763\n+ BR = 8.29\n+ IKR = 0.09\n+ VAR = 17.9\n+ RB = 10\n+ IRB = 5E-06\n+ RBM = 5\n+ RE = 0.649\n+ RC = 0.7014\n+ CJE = 1.244E-11\n+ VJE = 0.7579\n+ MJE = 0.3656\n+ TF = 4.908E-10\n+ XTF = 9.51\n+ VTF = 2.927\n+ ITF = 0.3131\n+ PTF = 0\n+ CJC = 3.347E-12\n+ VJC = 0.5463\n+ MJC = 0.391\n+ XCJC = 0.6193\n+ TR = 9E-08\n+ CJS = 0\n+ VJS = 0.75\n+ MJS = 0.333\n+ XTB = 0\n+ XTI = 3\n+ EG = 1.11\n+ FC = 0.979.

Linewraps are going to be a problem - delete all "\n" from the last few lines

I think I've put in a dual transistor where it might be useful. Dropping R28 to 15k made the start up appreciably tidier - nothing goes into saturation. Increasing the damping resistor at R6 to 82k means that the start-up is dead-beat.

It probably doesn't help the distortion - the 4th harmonic is only 125dB below the fundamental. I don't much like the 10uF film capacitor at C4 - it's going to be bulky and expensive, but something smaller is going to give you a little more distortion.

Vote

C

Cursitor Doom 1 year ago

"Please don't feed the troll."

Vote

E

Edward Rawde 1 year ago

"Bill Sloman" snipped-for-privacy@ieee.org wrote in message news:vsnufh$2ou7j$ snipped-for-privacy@dont-email.me...

...

Yes, that works but only 120dB down at 4KHz. I put the damping resistor back to 47k since I don't care what happens during the first few seonds as long as it happens. If it's necessary to wait one minute for the purest tone, that's fine with me.

You don't want to remove \n just remove the wraps.

BCM61B does not have two independent transistors.

So you probably want BCM847BS which has two independent matched transistors and a very low price at digikey, so may as well use two of them as shown below.

I took the model from

formatting link

It should only be necessary to unwrap the last line of the following. Don't remove \n just remove the wraps, you may need to use a horizontal scroll bar.

Version 4.1 SHEET 1 3020 2548 WIRE 80 -208 -288 -208 WIRE 800 -208 160 -208 WIRE -288 -96 -288 -208 WIRE 80 -96 -288 -96 WIRE 400 -96 160 -96 WIRE -288 32 -288 -96 WIRE -176 32 -288 32 WIRE -32 32 -96 32 WIRE 48 32 -32 32 WIRE 208 32 128 32 WIRE 256 32 208 32 WIRE 400 32 400 -96 WIRE 400 32 320 32 WIRE 464 32 400 32 WIRE 608 32 544 32 WIRE 656 32 608 32 WIRE 800 32 800 -208 WIRE 800 32 720 32 WIRE -752 48 -816 48 WIRE -624 48 -688 48 WIRE -288 144 -288 32 WIRE -176 144 -288 144 WIRE 208 144 208 32 WIRE 256 144 208 144 WIRE 608 144 608 32 WIRE 656 144 608 144 WIRE -816 160 -816 48 WIRE -752 160 -816 160 WIRE -624 160 -624 48 WIRE -624 160 -672 160 WIRE -32 160 -32 32 WIRE -32 160 -112 160 WIRE 400 160 400 32 WIRE 400 160 320 160 WIRE 800 160 800 32 WIRE 800 160 720 160 WIRE 832 160 800 160 WIRE -176 176 -288 176 WIRE 256 176 224 176 WIRE 656 176 624 176 WIRE 224 208 224 176 WIRE 624 208 624 176 WIRE -1968 224 -1968 144 WIRE -1008 272 -1104 272 WIRE -816 272 -816 160 WIRE -816 272 -944 272 WIRE -736 272 -816 272 WIRE -624 288 -624 160 WIRE -624 288 -672 288 WIRE -544 288 -624 288 WIRE -416 288 -480 288 WIRE -288 288 -288 176 WIRE -288 288 -336 288 WIRE -208 288 -288 288 WIRE 208 288 -128 288 WIRE 400 288 400 160 WIRE 400 288 208 288 WIRE -736 304 -816 304 WIRE -816 336 -816 304 WIRE 400 336 400 288 WIRE -1968 400 -1968 304 WIRE -1856 400 -1968 400 WIRE -1664 400 -1776 400 WIRE 208 400 208 288 WIRE 208 400 -1600 400 WIRE 400 448 400 416 WIRE 544 448 400 448 WIRE 368 464 336 464 WIRE -1968 496 -1968 400 WIRE -1968 496 -2304 496 WIRE 368 496 368 464 WIRE 400 496 400 448 WIRE 544 496 544 448 WIRE -2432 544 -2432 496 WIRE -2304 560 -2304 496 WIRE -2240 560 -2304 560 WIRE -2144 560 -2176 560 WIRE 384 608 384 560 WIRE 544 608 544 576 WIRE 544 608 384 608 WIRE -1968 640 -1968 496 WIRE -32 656 -32 160 WIRE 208 656 208 400 WIRE 384 656 384 608 WIRE 800 656 800 160 WIRE -2304 672 -2304 560 WIRE -2256 672 -2304 672 WIRE -2144 688 -2144 560 WIRE -2144 688 -2192 688 WIRE -2032 688 -2144 688 WIRE -2432 704 -2432 624 WIRE -2256 704 -2432 704 WIRE -2432 736 -2432 704 WIRE -2432 736 -2544 736 WIRE -32 752 -32 720 WIRE 208 752 208 720 WIRE 384 752 384 720 WIRE 800 752 800 720 WIRE -2544 768 -2544 736 WIRE -2432 768 -2432 736 WIRE -1360 800 -1360 704 WIRE -2544 864 -2544 832 WIRE -32 880 -32 832 WIRE 208 880 208 832 WIRE 208 880 -32 880 WIRE 384 880 384 832 WIRE 384 880 208 880 WIRE 800 880 800 832 WIRE 800 880 384 880 WIRE -2432 912 -2432 848 WIRE -1360 960 -1360 880 WIRE -1104 960 -1104 272 WIRE -1104 960 -1360 960 WIRE -32 976 -32 880 WIRE -320 992 -416 992 WIRE -160 992 -256 992 WIRE -416 1072 -416 992 WIRE -368 1072 -416 1072 WIRE -256 1072 -304 1072 WIRE -160 1072 -160 992 WIRE -160 1072 -176 1072 WIRE -2160 1152 -2160 1040 WIRE -1664 1152 -1664 1040 WIRE -160 1184 -160 1072 WIRE -160 1184 -240 1184 WIRE -32 1184 -32 1056 WIRE -32 1184 -160 1184 WIRE 48 1184 -32 1184 WIRE 176 1184 128 1184 WIRE 320 1184 240 1184 WIRE -1968 1200 -1968 736 WIRE -1968 1200 -2096 1200 WIRE -1904 1200 -1968 1200 WIRE -1728 1200 -1904 1200 WIRE -416 1200 -416 1072 WIRE -416 1200 -1088 1200 WIRE -304 1200 -416 1200 WIRE -2480 1216 -2480 1184 WIRE -2480 1216 -2528 1216 WIRE -208 1216 -240 1216 WIRE -2528 1232 -2528 1216 WIRE -1360 1232 -1360 960 WIRE -2480 1248 -2480 1216 WIRE -1664 1280 -1664 1248 WIRE -1424 1280 -1664 1280 WIRE -208 1328 -208 1216 WIRE -1664 1360 -1664 1280 WIRE -1360 1440 -1360 1328 WIRE -1664 1504 -1664 1440 WIRE -2160 1648 -2160 1248 WIRE -1648 1648 -2160 1648 WIRE -1088 1648 -1088 1200 WIRE -1088 1648 -1568 1648 WIRE -1904 1712 -1904 1200 WIRE -2160 1760 -2160 1648 WIRE -1968 1760 -2160 1760 WIRE -1904 1888 -1904 1808 FLAG 224 208 0 FLAG 624 208 0 FLAG 832 160 vout FLAG -272 1168 vcc FLAG -272 1232 vee FLAG -2528 1232 0 FLAG -2480 1104 vcc FLAG -2480 1328 vee FLAG -144 128 vcc FLAG -144 192 vee FLAG 288 128 vcc FLAG 288 192 vee FLAG 688 128 vcc FLAG 688 192 vee FLAG 336 464 0 FLAG 416 528 vcc FLAG 352 528 vee FLAG -2224 656 vcc FLAG -1968 144 vcc FLAG -2224 720 vee FLAG -1360 704 vcc FLAG -2432 496 vcc FLAG -2432 912 0 FLAG -1360 1440 0 FLAG -704 256 vcc FLAG -704 320 vee FLAG -816 336 0 FLAG -1664 1504 vee FLAG -1904 1888 0 FLAG -1664 1040 vcc FLAG -2160 1040 vcc FLAG -208 1328 0 FLAG -2544 864 0 FLAG 320 1184 vee SYMBOL res -80 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 10K SYMBOL res 144 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 16K SYMBOL res 560 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 16K SYMBOL cap 320 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 10n SYMBOL cap 720 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 10n SYMBOL res 176 -224 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 10K SYMBOL res 176 -80 M270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R5 SYMATTR Value 82k SYMBOL cap -256 976 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C3 SYMATTR Value 1000n SYMBOL res 32 1200 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R10 SYMATTR Value 820K SYMBOL diode 176 1200 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D1 SYMATTR Value 1N914 SYMBOL res -48 960 R0 SYMATTR InstName R11 SYMATTR Value 40.2K SYMBOL res 560 592 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R18 SYMATTR Value 10K SYMBOL res 416 432 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R19 SYMATTR Value 10k SYMBOL diode -16 656 M0 SYMATTR InstName D2 SYMATTR Value 1N914 SYMBOL diode 224 656 M0 SYMATTR InstName D12 SYMATTR Value 1N914 SYMBOL diode 368 656 R0 SYMATTR InstName D13 SYMATTR Value 1N914 SYMBOL diode 816 656 M0 SYMATTR InstName D14 SYMATTR Value 1N914 SYMBOL res -48 736 R0 SYMATTR InstName R13 SYMATTR Value 68k SYMBOL res 192 736 R0 SYMATTR InstName R14 SYMATTR Value 68k SYMBOL res 400 736 M0 SYMATTR InstName R15 SYMATTR Value 68k SYMBOL res 784 736 R0 SYMATTR InstName R16 SYMATTR Value 68k SYMBOL voltage -2480 1088 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V3 SYMATTR Value 15 SYMBOL voltage -2480 1232 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V4 SYMATTR Value 15 SYMBOL OpAmps\\LT1679 -144 160 R0 SYMATTR InstName U5 SYMBOL OpAmps\\LT1679 288 160 R0 SYMATTR InstName U6 SYMBOL OpAmps\\LT1679 688 160 R0 SYMATTR InstName U8 SYMBOL res -112 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R8 SYMATTR Value 10k SYMBOL res -320 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value 560 SYMBOL cap -480 272 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C8 SYMATTR Value 1000n SYMBOL res -272 1088 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R6 SYMATTR Value 47k SYMBOL cap -304 1056 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C4 SYMATTR Value 10000n SYMBOL OpAmps\\LT1679 384 528 R90 WINDOW 3 37 22 VRight 2 SYMATTR InstName U1 SYMBOL pnp -2032 736 M180 WINDOW 3 84 0 Left 2 SYMATTR Value 2N3906 SYMATTR InstName Q5 SYMBOL res -1984 208 R0 SYMATTR InstName R12 SYMATTR Value 56k SYMBOL res -1760 384 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R25 SYMATTR Value 2.7Meg SYMBOL cap -2176 544 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C7 SYMATTR Value 10p SYMBOL npn -2096 1152 M0 SYMATTR InstName Q2A SYMATTR Value BCM847BS SYMBOL npn -1424 1232 R0 SYMATTR InstName Q2B SYMATTR Value BCM847BS SYMBOL res -1552 1632 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R28 SYMATTR Value 15k SYMBOL res -1376 784 R0 SYMATTR InstName R29 SYMATTR Value 100k SYMBOL res -2448 528 R0 SYMATTR InstName R32 SYMATTR Value 10k SYMBOL res -2448 752 R0 SYMATTR InstName R33 SYMATTR Value 15k SYMBOL cap -944 256 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C12 SYMATTR Value 1000n SYMBOL res -656 144 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R7 SYMATTR Value 14k SYMBOL cap -688 32 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C5 SYMATTR Value 10p SYMBOL cap -1600 384 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C6 SYMATTR Value 100n SYMBOL res -1648 1456 R180 WINDOW 0 31 76 Left 2 WINDOW 3 31 40 Left 2 SYMATTR InstName R17 SYMATTR Value 120k SYMBOL OpAmps\\LT1679 -704 288 R0 SYMATTR InstName U2 SYMBOL OpAmps\\LT1679 -272 1200 M0 SYMATTR InstName U3 SYMBOL OpAmps\\LT1679 -2224 688 R0 SYMATTR InstName U4 SYMBOL cap -2560 768 R0 SYMATTR InstName C9 SYMATTR Value 10n SYMBOL npn -1728 1152 R0 SYMATTR InstName Q1A SYMATTR Value BCM847BS SYMBOL npn -1968 1712 R0 SYMATTR InstName Q1B SYMATTR Value BCM847BS TEXT -2792 1560 Left 2 !.tran 0 10 0 1u startup TEXT -2792 1504 Left 2 !.options plotwinsize=0 numdgt=15 TEXT -2976 32 Left 2 ;Low distortion 1KHz oscillator. Edward Rawde 30 March 2025. TEXT -2976 72 Left 2 ;Based on designs by JM and BS, and now modified again by Bill Sloman TEXT -1856 -48 Left 2 !.MODEL BCM847BS NPN IS = 1.822E-14 NF = 0.9932 ISE= 2.894E-16 NE = 1.4 \n+ BF = 324.4 IKF = 0.109 VAF = 82 NR = 0.9931 ISC = 9.982E-12 NC = 1.763 \n+ BR = 8.29 IKR = 0.09 VAR = 17.9 RB = 10 IRB = 5E-06 RBM = 5 RE = 0.649 \n+ RC = 0.7014 CJE =

1.244E-11 VJE = 0.7579 MJE = 0.3656 TF = 4.908E-10 \n+ XTF = 9.51 VTF = 2.927 ITF = 0.3131 PTF = 0 CJC = 3.347E-12 VJC = 0.5463 \n+ MJC = 0.391 XCJC = 0.6193 TR = 9E-08 CJS = 0 VJS = 0.75 MJS = 0.333 \n+ XTB = 0 XTI = 3 EG = 1.11 FC = 0.979

Vote

I

invalid unparseable 1 year ago

The point here is that some people, especially fatheads with advanced degrees, are incapable of having ideas, and react by being hostile to ideas and to people who have them.

Even goofy ideas sometimes evolve into great ideas, if they are not murdered at birth.

Electronic design, if it's not a routine mechanical activity, is about ideas.

Vote

E

Edward Rawde 1 year ago

Just remove three wraps at line 407, keeping your horizontal scroll bar pushed to the left each time. Now the last line should be 406 beginning with TEXT

Vote

J

JM 1 year ago

On Fri, 4 Apr 2025 14:25:29 -0400, "Edward Rawde" snipped-for-privacy@invalid.invalid wrote:

Best to just offset the integrator output so the amplitude is brought under control sooner.

Version 4 SHEET 1 3020 2548 WIRE -1936 -288 -1936 -336 WIRE -240 -208 -608 -208 WIRE 480 -208 -160 -208 WIRE -1936 -160 -1936 -208 WIRE -1840 -160 -1936 -160 WIRE -1648 -160 -1760 -160 WIRE 80 -160 -1584 -160 WIRE -608 -96 -608 -208 WIRE -240 -96 -608 -96 WIRE 80 -96 80 -160 WIRE 80 -96 -160 -96 WIRE -1936 -64 -1936 -160 WIRE -1936 -64 -2272 -64 WIRE -2400 -32 -2400 -288 WIRE -2272 0 -2272 -64 WIRE -2208 0 -2272 0 WIRE -2112 0 -2144 0 WIRE -608 32 -608 -96 WIRE -496 32 -608 32 WIRE -352 32 -416 32 WIRE -272 32 -352 32 WIRE -112 32 -192 32 WIRE -64 32 -112 32 WIRE 80 32 80 -96 WIRE 80 32 0 32 WIRE 144 32 80 32 WIRE 288 32 224 32 WIRE 336 32 288 32 WIRE 480 32 480 -208 WIRE 480 32 400 32 WIRE -1328 48 -1328 0 WIRE -1008 48 -1072 48 WIRE -880 48 -944 48 WIRE -1936 64 -1936 -64 WIRE -2272 96 -2272 0 WIRE -2224 96 -2272 96 WIRE -2112 112 -2112 0 WIRE -2112 112 -2160 112 WIRE -2000 112 -2112 112 WIRE -2400 128 -2400 48 WIRE -2224 128 -2400 128 WIRE -608 144 -608 32 WIRE -496 144 -608 144 WIRE -112 144 -112 32 WIRE -64 144 -112 144 WIRE 288 144 288 32 WIRE 336 144 288 144 WIRE -2400 160 -2400 128 WIRE -2400 160 -2512 160 WIRE -1072 160 -1072 48 WIRE -1008 160 -1072 160 WIRE -880 160 -880 48 WIRE -880 160 -928 160 WIRE -352 160 -352 32 WIRE -352 160 -432 160 WIRE 80 160 80 32 WIRE 80 160 0 160 WIRE 480 160 480 32 WIRE 480 160 400 160 WIRE 512 160 480 160 WIRE -496 176 -608 176 WIRE -64 176 -96 176 WIRE 336 176 304 176 WIRE -2512 192 -2512 160 WIRE -2400 192 -2400 160 WIRE -96 208 -96 176 WIRE 304 208 304 176 WIRE -1680 224 -1680 0 WIRE -1472 224 -1472 0 WIRE -1936 272 -1936 160 WIRE -1744 272 -1936 272 WIRE -1536 272 -1744 272 WIRE -1328 272 -1328 128 WIRE -1168 272 -1328 272 WIRE -1072 272 -1072 160 WIRE -1072 272 -1104 272 WIRE -992 272 -1072 272 WIRE -2512 288 -2512 256 WIRE -880 288 -880 160 WIRE -880 288 -928 288 WIRE -832 288 -880 288 WIRE -736 288 -768 288 WIRE -608 288 -608 176 WIRE -608 288 -656 288 WIRE -528 288 -608 288 WIRE -112 288 -448 288 WIRE 80 288 80 160 WIRE 80 288 -112 288 WIRE -1936 304 -1936 272 WIRE -1328 304 -1328 272 WIRE -992 304 -1072 304 WIRE -2400 336 -2400 272 WIRE -1072 336 -1072 304 WIRE 80 336 80 288 WIRE -1680 352 -1680 320 WIRE -1680 352 -1872 352 WIRE -1472 352 -1472 320 WIRE -1392 352 -1472 352 WIRE 80 448 80 416 WIRE 224 448 80 448 WIRE 48 464 16 464 WIRE -1680 480 -1680 352 WIRE -1472 480 -1472 352 WIRE 48 496 48 464 WIRE 80 496 80 448 WIRE 224 496 224 448 WIRE -1936 512 -1936 400 WIRE -1328 512 -1328 400 WIRE -1472 592 -1472 560 WIRE 64 608 64 560 WIRE 224 608 224 576 WIRE 224 608 64 608 WIRE -352 656 -352 160 WIRE -112 656 -112 288 WIRE 64 656 64 608 WIRE 480 656 480 160 WIRE -352 752 -352 720 WIRE -112 752 -112 720 WIRE 64 752 64 720 WIRE 480 752 480 720 WIRE -1936 800 -1936 768 WIRE -1936 800 -1984 800 WIRE -1984 816 -1984 800 WIRE -1936 832 -1936 800 WIRE -864 864 -960 864 WIRE -704 864 -800 864 WIRE -352 880 -352 832 WIRE -112 880 -112 832 WIRE -112 880 -352 880 WIRE 64 880 64 832 WIRE 64 880 -112 880 WIRE 144 880 64 880 WIRE 480 880 480 832 WIRE 480 880 144 880 WIRE -352 928 -352 880 WIRE 144 928 144 880 WIRE -960 944 -960 864 WIRE -912 944 -960 944 WIRE -800 944 -848 944 WIRE -704 944 -704 864 WIRE -704 944 -720 944 WIRE -704 1056 -704 944 WIRE -704 1056 -784 1056 WIRE -352 1056 -352 1008 WIRE -352 1056 -704 1056 WIRE -272 1056 -352 1056 WIRE -144 1056 -192 1056 WIRE 0 1056 -80 1056 WIRE -1680 1072 -1680 560 WIRE -1168 1072 -1680 1072 WIRE -960 1072 -960 944 WIRE -960 1072 -1104 1072 WIRE -848 1072 -960 1072 WIRE -752 1088 -784 1088 WIRE -1680 1104 -1680 1072 WIRE -752 1200 -752 1088 WIRE -1680 1232 -1680 1184 FLAG -96 208 0 FLAG 304 208 0 FLAG 512 160 vout FLAG -816 1040 vcc FLAG -816 1104 vee FLAG -1984 816 0 FLAG -1936 688 vcc FLAG -1936 912 vee FLAG -464 128 vcc FLAG -464 192 vee FLAG -32 128 vcc FLAG -32 192 vee FLAG 368 128 vcc FLAG 368 192 vee FLAG 16 464 0 FLAG 96 528 vcc FLAG 32 528 vee FLAG -2192 80 vcc FLAG -1936 -336 vcc FLAG -2192 144 vee FLAG -1328 0 vcc FLAG -2400 -288 vcc FLAG -2400 336 0 FLAG -1328 512 0 FLAG -960 256 vcc FLAG -960 320 vee FLAG -1072 336 0 FLAG -1472 592 vee FLAG -1936 512 0 FLAG -1472 0 vcc FLAG -1680 0 vcc FLAG -752 1200 0 FLAG -2512 288 0 FLAG 0 1056 vee FLAG -1680 1232 vee FLAG 144 992 0 SYMBOL res -400 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 10K SYMBOL res -176 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 16K SYMBOL res 240 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 16K SYMBOL cap 0 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 10n SYMBOL cap 400 16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 10n SYMBOL res -144 -224 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 10K SYMBOL res -144 -80 M270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R5 SYMATTR Value 82k SYMBOL cap -800 848 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C3 SYMATTR Value 1000n SYMBOL res -288 1072 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R10 SYMATTR Value 330k SYMBOL diode -144 1072 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D1 SYMATTR Value 1N914 SYMBOL res -368 912 R0 SYMATTR InstName R11 SYMATTR Value 40.2K SYMBOL res 240 592 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R18 SYMATTR Value 10K SYMBOL res 96 432 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R19 SYMATTR Value 10k SYMBOL diode -336 656 M0 SYMATTR InstName D2 SYMATTR Value 1N914 SYMBOL diode -96 656 M0 SYMATTR InstName D12 SYMATTR Value 1N914 SYMBOL diode 48 656 R0 SYMATTR InstName D13 SYMATTR Value 1N914 SYMBOL diode 496 656 M0 SYMATTR InstName D14 SYMATTR Value 1N914 SYMBOL res -368 736 R0 SYMATTR InstName R13 SYMATTR Value 68k SYMBOL res -128 736 R0 SYMATTR InstName R14 SYMATTR Value 68k SYMBOL res 80 736 M0 SYMATTR InstName R15 SYMATTR Value 68k SYMBOL res 464 736 R0 SYMATTR InstName R16 SYMATTR Value 68k SYMBOL voltage -1936 672 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V3 SYMATTR Value 15 SYMBOL voltage -1936 816 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V4 SYMATTR Value 15 SYMBOL OpAmps\\LT1679 -464 160 R0 SYMATTR InstName U5 SYMBOL OpAmps\\LT1679 -32 160 R0 SYMATTR InstName U6 SYMBOL OpAmps\\LT1679 368 160 R0 SYMATTR InstName U8 SYMBOL res -432 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R8 SYMATTR Value 10k SYMBOL res -640 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value 560 SYMBOL cap -768 272 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C8 SYMATTR Value 1000n SYMBOL res -816 960 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R6 SYMATTR Value 47k SYMBOL cap -848 928 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C4 SYMATTR Value 10000n SYMBOL OpAmps\\LT1679 64 528 R90 WINDOW 3 37 22 VRight 2 SYMATTR InstName U1 SYMBOL pnp -2000 160 M180 WINDOW 3 84 0 Left 2 SYMATTR Value 2N3906 SYMATTR InstName Q5 SYMBOL res -1952 -304 R0 SYMATTR InstName R12 SYMATTR Value 56k SYMBOL res -1744 -176 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R25 SYMATTR Value 2.7Meg SYMBOL cap -2144 -16 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C7 SYMATTR Value 10p SYMBOL npn -1744 224 R0 SYMATTR InstName Q2A SYMATTR Value BCM847BS SYMBOL npn -1392 304 R0 SYMATTR InstName Q2B SYMATTR Value BCM847BS SYMBOL res -1664 576 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R28 SYMATTR Value 120k SYMBOL res -1344 32 R0 SYMATTR InstName R29 SYMATTR Value 100k SYMBOL res -2416 -48 R0 SYMATTR InstName R32 SYMATTR Value 10k SYMBOL res -2416 176 R0 SYMATTR InstName R33 SYMATTR Value 15k SYMBOL cap -1104 256 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C12 SYMATTR Value 1000n SYMBOL res -912 144 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R7 SYMATTR Value 14k SYMBOL cap -944 32 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C5 SYMATTR Value 10p SYMBOL cap -1584 -176 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C6 SYMATTR Value 100n SYMBOL res -1456 576 R180 WINDOW 0 31 76 Left 2 WINDOW 3 31 40 Left 2 SYMATTR InstName R17 SYMATTR Value 120k SYMBOL OpAmps\\LT1679 -960 288 R0 SYMATTR InstName U2 SYMBOL OpAmps\\LT1679 -816 1072 M0 SYMATTR InstName U3 SYMBOL OpAmps\\LT1679 -2192 112 R0 SYMATTR InstName U4 SYMBOL cap -2528 192 R0 SYMATTR InstName C9 SYMATTR Value 10n SYMBOL npn -1536 224 R0 SYMATTR InstName Q1A SYMATTR Value BCM847BS SYMBOL npn -1872 304 M0 SYMATTR InstName Q1B SYMATTR Value BCM847BS SYMBOL zener -1168 1088 R270 WINDOW 0 36 32 VTop 2 WINDOW 3 -4 32 VBottom 2 SYMATTR InstName D3 SYMATTR Value BZX84B13VLY SYMBOL res -1696 1088 R0 SYMATTR InstName R20 SYMATTR Value 2k SYMBOL cap 128 928 R0 SYMATTR InstName C10 SYMATTR Value 100n TEXT -2576 632 Left 2 !.tran 0 10 0 1u startup TEXT -2576 576 Left 2 !.options plotwinsize=0 numdgt=15 TEXT -2688 1104 Left 2 !.MODEL BCM847BS NPN IS = 1.822E-14 NF = 0.9932 ISE= 2.894E-16 NE = 1.4 \n+ BF = 324.4 IKF = 0.109 VAF = 82 NR =

0.9931 ISC = 9.982E-12 NC = 1.763 \n+ BR = 8.29 IKR = 0.09 VAR = 17.9 RB = 10 IRB = 5E-06 RBM = 5 RE = 0.649 \n+ RC = 0.7014 CJE = 1.244E-11 VJE = 0.7579 MJE = 0.3656 TF = 4.908E-10 \n+ XTF = 9.51 VTF = 2.927 ITF = 0.3131 PTF = 0 CJC = 3.347E-12 VJC = 0.5463 \n+ MJC = 0.391 XCJC = 0.6193 TR = 9E-08 CJS = 0 VJS = 0.75 MJS = 0.333 \n+ XTB = 0 XTI = 3 EG = 1.11 FC = 0.979

Vote

E

Edward Rawde 1 year ago

Wow. That has much lower distortion too.

Vote

Low distortion sinewave oscillator without big capacitor.

Join the Discussion

Didn't find your answer?