Clipping/peak Indicator Circuit Help

Except that it doesn't, per the OP. It's a complete hairball. Just for openers, avalanching a LED doesn't make it light significantly. (Try it.)

Build that circuit with lead-free solder and water soluble flux, and all those resistances become uncertain by two or three orders of magnitude.

Every once in awhile you run into a good reasons to rely on untested parameters of some part or another, but blinking a LED to the music isn't one of them.

Cheers

Phil Hobbs

That's what they say...there's something they're not telling us about those LEDs.

We don't know what the original circuit called for, the hobby cultists star ted circulating the schematic assuming it was all they needed to know, but the Elektor article probably called for standoff mounting and flying leads.

I think it's supposed to be used to set drive levels to things like amplifi ers and not for some kind of light display synchronized to music. The only strange part about the circuit is separate positive and negative peak thres holds adjs, you would think they should be the same.

On Thursday, February 13, 2014 10:41:06 PM UTC-5, snipped-for-privacy@gmail.com

fiers and not for some kind of light display synchronized to music. The onl y strange part about the circuit is separate positive and negative peak thr esholds adjs, you would think they should be the same.

Errr...left and right channel...

well.

I disagree. It is a lot better than the first circuit. It sees both positive and negative over excursions. C5 is a pulse stretcher.

?-)

A surprising number of LEDs spec their abs max reverse bias at 3V. This means many LED driver chips stress the LEDs.

If you actually avalanche them, they will become leaky.

I think this is just laziness on the part of LED manufacturers. I haven't found an LED that avalanches at less than 20V. (But if you have actually tested some, then please post a part number.)

Well in my experience if you limit the current such that the total power disipation is less than ~50mW (whatever the forward biased max power is.) then there is no harm done.

George h.

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Aarghhh...

Careless problems with the front end; sorry 'bout that. :-(

I'll post the fix some time this weekend. :-)

John Fields

Prepare for PAL with HUB attack, engineering honesty is not tolerated and will be subject to derision. ...Jim Thompson

On Sat, 15 Feb 2014 07:12:56 -0600, John Fields wrote:

--- Version 4 SHEET 1 1620 1624 WIRE 224 864 -336 864 WIRE 384 864 224 864 WIRE 608 864 384 864 WIRE 848 864 608 864 WIRE 944 864 848 864 WIRE 1008 864 944 864 WIRE 1168 864 1088 864 WIRE 1152 880 1120 880 WIRE 1232 880 1184 880 WIRE 1168 896 1168 864 WIRE 224 912 224 864 WIRE 384 912 384 864 WIRE 608 912 608 864 WIRE 848 912 848 864 WIRE 944 912 944 864 WIRE -64 944 -48 928 WIRE -64 944 -192 944 WIRE -32 944 -48 928 WIRE 96 944 -32 944 WIRE -208 960 -192 944 WIRE 112 960 96 944 WIRE 1168 1008 1168 976 WIRE 496 1024 496 1008 WIRE 384 1040 384 992 WIRE 464 1040 384 1040 WIRE 608 1056 608 992 WIRE 608 1056 528 1056 WIRE 224 1072 224 992 WIRE 288 1072 224 1072 WIRE 464 1072 288 1072 WIRE 1040 1072 1040 1056 WIRE 1120 1072 1120 880 WIRE 1152 1072 1120 1072 WIRE 1232 1072 1232 880 WIRE 1232 1072 1184 1072 WIRE -208 1088 -208 1072 WIRE -48 1088 -48 1072 WIRE 112 1088 112 1072 WIRE 944 1088 944 992 WIRE 1008 1088 944 1088 WIRE 224 1104 224 1072 WIRE 1168 1104 1168 1072 WIRE 1168 1104 1072 1104 WIRE 848 1120 848 992 WIRE 1008 1120 848 1120 WIRE 384 1136 384 1040 WIRE 384 1136 352 1136 WIRE 496 1136 496 1088 WIRE 496 1136 464 1136 WIRE 1040 1152 1040 1136 WIRE 1040 1152 992 1152 WIRE 1040 1168 1040 1152 WIRE 496 1184 496 1136 WIRE 848 1184 848 1120 WIRE 1008 1184 848 1184 WIRE 384 1200 384 1136 WIRE 464 1200 384 1200 WIRE 1168 1200 1168 1104 WIRE 1168 1200 1072 1200 WIRE 608 1216 608 1056 WIRE 608 1216 528 1216 WIRE 640 1216 608 1216 WIRE 736 1216 704 1216 WIRE 848 1216 848 1184 WIRE 848 1216 816 1216 WIRE 944 1216 944 1088 WIRE 1008 1216 944 1216 WIRE 224 1232 224 1184 WIRE 288 1232 224 1232 WIRE 464 1232 288 1232 WIRE -64 1248 -112 1248 WIRE 64 1248 16 1248 WIRE 112 1248 64 1248 WIRE 224 1248 224 1232 WIRE 224 1248 176 1248 WIRE 1040 1248 1040 1232 WIRE -336 1264 -336 864 WIRE -304 1264 -336 1264 WIRE 496 1264 496 1248 WIRE -336 1296 -336 1264 WIRE -112 1296 -112 1248 WIRE 64 1296 64 1248 WIRE 224 1296 224 1248 WIRE 384 1296 384 1200 WIRE 848 1296 848 1216 WIRE 944 1296 944 1216 WIRE -336 1392 -336 1376 WIRE -304 1392 -336 1392 WIRE -336 1424 -336 1392 WIRE -112 1424 -112 1376 WIRE -112 1424 -336 1424 WIRE 64 1424 64 1376 WIRE 64 1424 -112 1424 WIRE 224 1424 224 1376 WIRE 224 1424 64 1424 WIRE 384 1424 384 1376 WIRE 384 1424 224 1424 WIRE 848 1424 848 1360 WIRE 848 1424 384 1424 WIRE 944 1424 944 1376 WIRE 944 1424 848 1424 WIRE -336 1488 -336 1424 FLAG -336 1488 0 FLAG -304 1264 +12 FLAG 496 1264 +12 FLAG 496 1008 +12 FLAG 992 1152 0V FLAG -304 1392 0V FLAG 1040 1056 +12 FLAG 1040 1248 +12 FLAG 464 1136 0V FLAG 288 1072 -PEAK FLAG 288 1232 +PEAK FLAG 352 1136 0.5V FLAG -208 1088 0 FLAG -48 1088 0 FLAG 112 1088 0 SYMBOL res 592 896 R0 SYMATTR InstName R8 SYMATTR Value 10k SYMBOL voltage -336 1280 R0 WINDOW 3 24 96 Invisible 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 WINDOW 0 41 60 Left 2 SYMATTR Value 12 SYMATTR InstName V1 SYMBOL res 864 896 M0 SYMATTR InstName R10 SYMATTR Value 1meg SYMBOL cap 864 1296 M0 SYMATTR InstName C2 SYMATTR Value 220n SYMBOL res 992 880 R270 WINDOW 0 -32 59 VTop 2 WINDOW 3 -32 59 VBottom 2 SYMATTR InstName R13 SYMATTR Value 430 SYMBOL LED 1152 1008 R0 WINDOW 0 -25 -3 Left 2 WINDOW 3 -23 29 Left 2 SYMATTR InstName D2 SYMBOL diode 704 1200 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName D1 SYMATTR Value 1N4148 SYMBOL res 832 1200 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value 1000 SYMBOL Comparators\\LT1017 1040 1200 M180 WINDOW 0 55 -60 Left 2 WINDOW 3 29 -30 Left 2 SYMATTR InstName U4 SYMBOL res 960 896 M0 WINDOW 0 -49 36 Left 2 WINDOW 3 -64 66 Left 2 SYMATTR InstName R11 SYMATTR Value 1meg SYMBOL res 960 1280 M0 WINDOW 0 -50 33 Left 2 WINDOW 3 -69 61 Left 2 SYMATTR InstName R12 SYMATTR Value 2meg SYMBOL Comparators\\LT1017 496 1056 R0 WINDOW 0 49 54 Left 2 WINDOW 3 23 27 Left 2 SYMATTR InstName U1 SYMBOL Comparators\\LT1017 496 1216 M180 WINDOW 0 38 -52 Left 2 WINDOW 3 22 -24 Left 2 SYMATTR InstName U2 SYMBOL res 368 1280 R0 SYMATTR InstName R7 SYMATTR Value 4320 SYMBOL res 368 896 R0 SYMATTR InstName R6 SYMATTR Value 100k SYMBOL Comparators\\LT1017 1040 1104 R0 WINDOW 0 54 50 Left 2 WINDOW 3 33 24 Left 2 SYMATTR InstName U3 SYMBOL voltage -48 976 R0 WINDOW 3 24 96 Invisible 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 WINDOW 0 -56 18 Left 2 SYMATTR Value SINE(0 1 10 1 0 0 0.5) SYMATTR InstName V4 SYMBOL voltage 112 976 R0 WINDOW 3 24 96 Invisible 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 WINDOW 0 -54 16 Left 2 SYMATTR Value SINE(0 1 10 1. 0 180 0.5) SYMATTR InstName V5 SYMBOL res 1152 880 R0 SYMATTR InstName RL SYMATTR Value 120 SYMBOL voltage -208 976 R0 WINDOW 3 24 96 Invisible 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 WINDOW 0 -52 18 Left 2 SYMATTR Value SINE(0 1 10) SYMATTR InstName V3 SYMBOL res 208 896 R0 SYMATTR InstName R3 SYMATTR Value 1.1meg SYMBOL res 208 1280 R0 SYMATTR InstName R5 SYMATTR Value 10k SYMBOL cap 176 1232 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1

SYMBOL res 208 1088 R0 SYMATTR InstName R4 SYMATTR Value 80.6k SYMBOL res 48 1280 R0 SYMATTR InstName R2 SYMATTR Value 990 SYMBOL res 32 1232 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 10 SYMBOL voltage -112 1280 R0 WINDOW 3 24 96 Invisible 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 WINDOW 0 26 14 Left 2 SYMATTR Value SINE(0 1 10 1. 0 180 .5) SYMATTR InstName V2 TEXT -64 1456 Right 2 !.tran 0 10s 0 startup uic TEXT 368 808 Left 2 ;PEAK DETECTOR TEXT 944 776 Left 2 ;RETRIGGERABLE TEXT 984 808 Left 2 ;ONE-SHOT TEXT -40 1456 Left 2 ;PEAK DETECTOR AND INDICATOR, REV D TEXT 488 1456 Left 2 ;JOHN FIELDS, 18 FEB 2014 TEXT 336 776 Left 2 ;POSITIVE AND NEGATIVE TEXT 1176 992 Left 2 ;LED TEXT -176 904 Left 2 ;FOR TEST, TEXT -48 904 Left 2 ;SUB FOR V2 TEXT -64 1152 Left 2 ;R1R2 = TEXT -112 1184 Left 2 ;1000 OHM POT TEXT -304 1040 Left 2 ;SINE TEXT -152 1040 Left 2 ;SINE TEXT -168 1072 Left 2 ;PULSE + TEXT 8 1040 Left 2 ;SINE TEXT -16 1072 Left 2 ;PULSE - TEXT -152 808 Left 2 ;INPUT ATTENUATOR