Colpitts kick-start in LT Spice

jlarkin · 2019-11-11T15:16:55+00:00

The 100-second interval, before the kick-start, does all sorts if fun stuff, but doesn't seem to want to oscillate. It's super sensitive to time step and Spice params. Version 4 SHEET 1 1348 680 WIRE 896 -144 672 -144 WIRE 672 -80 672 -144 WIRE 896 -32 896 -144 WIRE 240 0 112 0 WIRE 304 0 240 0 WIRE 464 0 304 0 WIRE 624 0 464 0 WIRE 464 80 464 0 WIRE 112 96 112 0 WIRE 304 112 304 0 WIRE 896 128 896 48 WIRE 896 128 816 128 WIRE 816 160 816 128 WIRE 464 192 464 144 WIRE 576 192 464 192 WIRE 672 192 672 16 WIRE 672 192 576 192 WIRE 464 240 464 192 WIRE 672 256 672 192 WIRE 896 256 896 128 WIRE 112 400 112 176 WIRE 304 400 304 192 WIRE 304 400 112 400 WIRE 464 400 464 304 WIRE 464 400 304 400 WIRE 672 400 672 336 WIRE 896 400 896 336 WIRE 896 400 672 400 WIRE 464 432 464 400 FLAG 240 0 OSC FLAG 464 432 0 FLAG 816 160 0 FLAG 576 192 SRC SYMBOL ind 288 96 R0 WINDOW 0 54 39 Left 2 WINDOW 3 60 70 Left 2 SYMATTR InstName L1 SYMATTR Value 1 SYMBOL cap 448 80 R0 WINDOW 0 51 20 Left 2 WINDOW 3 59 54 Left 2 SYMATTR InstName C1 SYMATTR Value 1 SYMBOL current 112 176 R180 WINDOW 0 63 41 Left 2 WINDOW 3 48 -4 Left 2 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName I1 SYMATTR Value PULSE(0 10 100 1m 1m 50m) SYMBOL cap 448 240 R0 WINDOW 0 51 20 Left 2 WINDOW 3 59 54 Left 2 SYMATTR InstName C2 SYMATTR Value 5 SYMBOL nmos 624 -80 R0 WINDOW 0 90 24 Left 2 WINDOW 3 70 58 Left 2 SYMATTR InstName M1 SYMATTR Value 2N7002 SYMBOL res 656 240 R0 WINDOW 0 61 43 Left 2 WINDOW 3 60 78 Left 2 SYMATTR InstName R1 SYMATTR Value 500 SYMBOL voltage 896 -48 R0 WINDOW 0 49 45 Left 2 WINDOW 3 48 80 Left 2 SYMATTR InstName V1 SYMATTR Value 20 SYMBOL voltage 896 240 R0 WINDOW 0 53 37 Left 2 WINDOW 3 57 72 Left 2 SYMATTR InstName V2 SYMATTR Value 20 TEXT -192 376 Left 2 !.tran 0 1000 0 200u TEXT -192 272 Left 2 ;Colpitts Kick-Start TEXT -168 312 Left 2 ;JL Nov 9 2019 -- John Larkin Highland Technology, Inc lunatic fringe electronics

Nov 11, 2019 44 Replies

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Clifford Heath 6 years ago

True, but the way they start and settle tells you quite a lot about the loop conditions, especially amplitude stability.

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John S 6 years ago

If you are unhappy with LTSpice, don't use it or make your own simulator. LTSpice is free. What's wrong with you?

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John Larkin 6 years ago

I'm not unhapy with LT. I love it. But any numerical simulation of a complex physical system will have weirdnesses and numerical instabilities and has to be driven carefully.

I have written my own circuit and control system simulators. But LT Spice is better. Well, one PLL could probably only be simulated with custom code.

You are more interested in being obnoxious than in designing electronics. What's wrong with you?

John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com

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Joseph Gwinn 6 years ago

On Nov 13, 2019, Steve Wilson wrote (in article):

available in the pdf version it appears), you will find background information and literature references. This usually solves the Hih? problem.

Joe Gwinn

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John S 6 years ago

PKB

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