John Larkin's LC oscillator
in [Basics]
|
Prev: Twin T circuit wanted
Next: And blocking oscillators
From: BlindBaby on 11 Jun 2010 19:07 On Fri, 11 Jun 2010 08:16:29 -0500, John Fields <jfields(a)austininstruments.com> wrote: >On Fri, 11 Jun 2010 07:02:03 -0500, John Fields ><jfields(a)austininstruments.com> wrote: > >>On 10 Jun 2010 13:23:55 -0700, Winfield Hill >><Winfield_member(a)newsguy.com> wrote: >> >> >>> In a ringing bell application, as the supply voltage sags, >>> and the amplitude drops, I imagine the circuit will move >>> from class C back to class A operation, before stopping. >> >>--- >>Why imagine? >> >>Here's a circuit list that'll show it all _and_ it'll create a .wav >>file, "bong.wav" in whatever folder the cicuit's in, so you can hear >>it. >> >>Enjoy! :-) > >--- >Oops... >Here it is: > >Version 4 >SHEET 1 936 680 >WIRE -384 48 -592 48 >WIRE -320 48 -384 48 >WIRE -112 48 -224 48 >WIRE 16 48 -112 48 >WIRE 112 48 16 48 >WIRE 16 64 16 48 >WIRE 112 64 112 48 >WIRE -384 96 -384 48 >WIRE -112 96 -112 48 >WIRE -448 144 -496 144 >WIRE 16 160 16 128 >WIRE 112 160 112 144 >WIRE 112 160 16 160 >WIRE -496 176 -496 144 >WIRE -592 192 -592 48 >WIRE -272 192 -272 112 >WIRE -272 192 -384 192 >WIRE 16 192 16 160 >WIRE -112 240 -112 176 >WIRE -48 240 -112 240 >WIRE -384 272 -384 192 >WIRE -272 272 -272 192 >WIRE -496 288 -496 256 >WIRE -112 304 -112 240 >WIRE 16 320 16 288 >WIRE 112 320 16 320 >WIRE 16 336 16 320 >WIRE 112 336 112 320 >WIRE -592 432 -592 272 >WIRE -496 432 -496 368 >WIRE -496 432 -592 432 >WIRE -384 432 -384 352 >WIRE -384 432 -496 432 >WIRE -272 432 -272 336 >WIRE -272 432 -384 432 >WIRE -112 432 -112 368 >WIRE -112 432 -272 432 >WIRE 16 432 16 416 >WIRE 16 432 -112 432 >WIRE 112 432 112 416 >WIRE 112 432 16 432 >WIRE -592 528 -592 432 >FLAG -592 528 0 >SYMBOL ind2 96 48 R0 >SYMATTR InstName L1 >SYMATTR Value 20e-3 >SYMATTR Type ind >SYMBOL ind2 96 432 M180 >WINDOW 0 36 80 Left 0 >WINDOW 3 36 40 Left 0 >SYMATTR InstName L2 >SYMATTR Value 500e-6 >SYMATTR Type ind >SYMATTR SpiceLine Rser=.01 >SYMBOL npn -48 192 R0 >SYMATTR InstName Q1 >SYMATTR Value 2N3904 >SYMBOL res -128 80 R0 >SYMATTR InstName R1 >SYMATTR Value 100k >SYMBOL cap 0 64 R0 >SYMATTR InstName C1 >SYMATTR Value 10e-6 >SYMBOL voltage -592 176 R0 >WINDOW 123 0 0 Left 0 >WINDOW 39 0 0 Left 0 >WINDOW 3 24 104 Invisible 0 >SYMATTR Value 5 >SYMATTR InstName V2 >SYMBOL pnp -448 192 M180 >SYMATTR InstName Q3 >SYMATTR Value 2N4403 >SYMBOL voltage -496 272 R0 >WINDOW 123 0 0 Left 0 >WINDOW 39 0 0 Left 0 >WINDOW 3 24 104 Invisible 0 >SYMATTR Value PULSE(5 0 0 1e-6 1e-6 .01) >SYMATTR InstName V1 >SYMBOL npn -320 112 R270 >SYMATTR InstName Q2 >SYMATTR Value 2N3904 >SYMBOL cap -288 272 R0 >SYMATTR InstName C4 >SYMATTR Value 1e-6 >SYMBOL res -400 256 R0 >SYMATTR InstName R2 >SYMATTR Value 100k >SYMBOL res -512 160 R0 >SYMATTR InstName R3 >SYMATTR Value 1000 >SYMBOL cap -128 304 R0 >SYMATTR InstName C2 >SYMATTR Value 1e-7 >SYMBOL res 0 320 R0 >SYMATTR InstName R4 >SYMATTR Value 750 >TEXT 32 184 Left 0 !K1 L1 L2 1 >TEXT -528 464 Left 0 !.tran 5 >TEXT -528 496 Left 0 !.wave .\\bong.wav 8 10000 N008 LT doesn't like all the SYMATTR use. It expects to only see it once.
From: ehsjr on 11 Jun 2010 21:20 John Fields wrote: > On Fri, 11 Jun 2010 07:02:03 -0500, John Fields > <jfields(a)austininstruments.com> wrote: > > >>On 10 Jun 2010 13:23:55 -0700, Winfield Hill >><Winfield_member(a)newsguy.com> wrote: >> >> >> >>>In a ringing bell application, as the supply voltage sags, >>>and the amplitude drops, I imagine the circuit will move >>>from class C back to class A operation, before stopping. >> >>--- >>Why imagine? >> >>Here's a circuit list that'll show it all _and_ it'll create a .wav >>file, "bong.wav" in whatever folder the cicuit's in, so you can hear >>it. >> >>Enjoy! :-) > > > --- > Oops... > Here it is: > > Version 4 > SHEET 1 936 680 > WIRE -384 48 -592 48 > WIRE -320 48 -384 48 > WIRE -112 48 -224 48 > WIRE 16 48 -112 48 > WIRE 112 48 16 48 > WIRE 16 64 16 48 > WIRE 112 64 112 48 > WIRE -384 96 -384 48 > WIRE -112 96 -112 48 > WIRE -448 144 -496 144 > WIRE 16 160 16 128 > WIRE 112 160 112 144 > WIRE 112 160 16 160 > WIRE -496 176 -496 144 > WIRE -592 192 -592 48 > WIRE -272 192 -272 112 > WIRE -272 192 -384 192 > WIRE 16 192 16 160 > WIRE -112 240 -112 176 > WIRE -48 240 -112 240 > WIRE -384 272 -384 192 > WIRE -272 272 -272 192 > WIRE -496 288 -496 256 > WIRE -112 304 -112 240 > WIRE 16 320 16 288 > WIRE 112 320 16 320 > WIRE 16 336 16 320 > WIRE 112 336 112 320 > WIRE -592 432 -592 272 > WIRE -496 432 -496 368 > WIRE -496 432 -592 432 > WIRE -384 432 -384 352 > WIRE -384 432 -496 432 > WIRE -272 432 -272 336 > WIRE -272 432 -384 432 > WIRE -112 432 -112 368 > WIRE -112 432 -272 432 > WIRE 16 432 16 416 > WIRE 16 432 -112 432 > WIRE 112 432 112 416 > WIRE 112 432 16 432 > WIRE -592 528 -592 432 > FLAG -592 528 0 > SYMBOL ind2 96 48 R0 > SYMATTR InstName L1 > SYMATTR Value 20e-3 > SYMATTR Type ind > SYMBOL ind2 96 432 M180 > WINDOW 0 36 80 Left 0 > WINDOW 3 36 40 Left 0 > SYMATTR InstName L2 > SYMATTR Value 500e-6 > SYMATTR Type ind > SYMATTR SpiceLine Rser=.01 > SYMBOL npn -48 192 R0 > SYMATTR InstName Q1 > SYMATTR Value 2N3904 > SYMBOL res -128 80 R0 > SYMATTR InstName R1 > SYMATTR Value 100k > SYMBOL cap 0 64 R0 > SYMATTR InstName C1 > SYMATTR Value 10e-6 > SYMBOL voltage -592 176 R0 > WINDOW 123 0 0 Left 0 > WINDOW 39 0 0 Left 0 > WINDOW 3 24 104 Invisible 0 > SYMATTR Value 5 > SYMATTR InstName V2 > SYMBOL pnp -448 192 M180 > SYMATTR InstName Q3 > SYMATTR Value 2N4403 > SYMBOL voltage -496 272 R0 > WINDOW 123 0 0 Left 0 > WINDOW 39 0 0 Left 0 > WINDOW 3 24 104 Invisible 0 > SYMATTR Value PULSE(5 0 0 1e-6 1e-6 .01) > SYMATTR InstName V1 > SYMBOL npn -320 112 R270 > SYMATTR InstName Q2 > SYMATTR Value 2N3904 > SYMBOL cap -288 272 R0 > SYMATTR InstName C4 > SYMATTR Value 1e-6 > SYMBOL res -400 256 R0 > SYMATTR InstName R2 > SYMATTR Value 100k > SYMBOL res -512 160 R0 > SYMATTR InstName R3 > SYMATTR Value 1000 > SYMBOL cap -128 304 R0 > SYMATTR InstName C2 > SYMATTR Value 1e-7 > SYMBOL res 0 320 R0 > SYMATTR InstName R4 > SYMATTR Value 750 > TEXT 32 184 Left 0 !K1 L1 L2 1 > TEXT -528 464 Left 0 !.tran 5 > TEXT -528 496 Left 0 !.wave .\\bong.wav 8 10000 N008 > Thanks! Sounds nice - now, whereinthehell is the icon for a "bongy" face? :-))) Ed
From: John Larkin on 11 Jun 2010 22:23 On Fri, 11 Jun 2010 13:49:00 -0700, BlindBaby <BlindMelonChitlin(a)wellnevergetthatonethealbumcover.org> wrote: >On Fri, 11 Jun 2010 12:28:41 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >> >>Lotta munbling. What does it mean? What causes it? > > "Munbling"? I don't know... it is not a word that I am aware of. > > Since you were the one that used it, maybe you could tell us. It's recursive mumbling, the sound you make when you mumble "mumble." John
From: BlindBaby on 11 Jun 2010 22:44 On Fri, 11 Jun 2010 19:23:03 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Fri, 11 Jun 2010 13:49:00 -0700, BlindBaby ><BlindMelonChitlin(a)wellnevergetthatonethealbumcover.org> wrote: > >>On Fri, 11 Jun 2010 12:28:41 -0700, John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>> >>>Lotta munbling. What does it mean? What causes it? >> >> "Munbling"? I don't know... it is not a word that I am aware of. >> >> Since you were the one that used it, maybe you could tell us. > >It's recursive mumbling, the sound you make when you mumble "mumble." > >John Yes, John... muMble is a word. "muNble", which is what you wrote, is not, idiot.
From: John Larkin on 11 Jun 2010 22:51
On Fri, 11 Jun 2010 17:43:39 -0300, YD <ydtechHAT(a)techie.com> wrote: >Late at night, by candle light, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> penned this immortal >opus: > >>On Fri, 11 Jun 2010 13:37:09 -0300, YD <ydtechHAT(a)techie.com> wrote: >> >>>Late at night, by candle light, Jeroen Belleman <jeroen(a)nospam.please> >>>penned this immortal opus: >>> >>>>John Larkin wrote: >>>>> >>>>> I like the way it works with a very high turns ratio, very small AC >>>>> drive at the emitter. But at lower ratios, it gets very nonlinear and >>>>> becomes, if that means anything, a tuned blocking oscillator. The base >>>>> capacitor value would be lowered so that the cap recharges a bunch >>>>> during a oscillatory cycle. >>>>> >>>>> I'm sure JT and JF will spend the next week diligently searching for a >>>>> set of values that will make my circuit not work. Then they'll crow, >>>>> or rather, cluck about it. That's OK: as Woody Allen says, we need the >>>>> eggs. >>>> >>>>I made it squeg. Maybe that will please them. >>>> >>> >>>Yes, the tank's Q must be kept high. Increasing La's series R makes it >>>squegg in a rather amusing way. Might be fun capturing it to a .wav. >> >>I always ran it with a big base capacitor. I'd expect that to prevent >>squegging, as the tank resonance/rectification thing should be 1st >>order, and 1st order loops are stable. A smaller base cap adds a >>second time-variant element in the right ballpark. >> >>> >>>JL: Can you recall ballpark the values of the inductors and associated >>>frequencies in the physical circuit? High valued Ls tend to be rather >>>resistive unless they're grossly oversized. >> >>Sorry, can't remember values after 35 years. >> > >Ok, here's my take on it. It does seem to work class C, with some >weird twists. The base is held practically constant, Q1 starts >conducting when the emitter is pulled below Vb-.6V. As the tank gets >close to Ve, there's a bit of suckage through bc, Vc ~= Ve. Then >there's another bit of kick, Ve goes up and turns off Q1. > >Depending on turns ratio Vb stabilizes somewhere between 0.5 and >-0.2V. A higher TR pulls it lower, makes sense. > >Adding about 1 or more ohms to L's Rs sets it squegging, haven't got >that really figured yet. > >I start saving data after it has settled to make the currents easier >resolved on the graph. > >Version 4 >SHEET 1 880 680 >WIRE 304 -64 16 -64 >WIRE 432 -64 304 -64 >WIRE 304 -32 304 -64 >WIRE 400 -32 304 -32 >WIRE 304 0 304 -32 >WIRE 400 0 400 -32 >WIRE 16 16 16 -64 >WIRE 256 96 176 96 >WIRE 304 96 304 64 >WIRE 304 96 256 96 >WIRE 400 96 400 80 >WIRE 400 96 304 96 >WIRE 176 144 176 96 >WIRE 432 160 432 -64 >WIRE 16 192 16 96 >WIRE 64 192 16 192 >WIRE 112 192 64 192 >WIRE 208 240 176 240 >WIRE 352 240 208 240 >WIRE 16 256 16 192 >WIRE 432 272 432 240 >WIRE 352 304 352 240 >WIRE 16 352 16 320 >WIRE 352 416 352 384 >FLAG 16 352 0 >FLAG 352 416 0 >FLAG 432 272 0 >FLAG 256 96 c >FLAG 64 192 b >FLAG 208 240 e >SYMBOL voltage 432 144 R0 >WINDOW 123 0 0 Left 0 >WINDOW 39 0 0 Left 0 >SYMATTR InstName V1 >SYMATTR Value 5 >SYMBOL npn 112 144 R0 >SYMATTR InstName Q1 >SYMATTR Value 2N3904 >SYMBOL ind2 384 -16 R0 >SYMATTR InstName L1 >SYMATTR Value 10m >SYMBOL ind2 336 400 M180 >WINDOW 0 36 80 Left 0 >WINDOW 3 36 40 Left 0 >SYMATTR InstName L2 >SYMATTR Value 25� >SYMATTR SpiceLine Rser=30m >SYMBOL res 0 0 R0 >SYMATTR InstName R1 >SYMATTR Value 100k >SYMBOL cap 288 0 R0 >SYMATTR InstName C1 >SYMATTR Value 1� >SYMATTR SpiceLine Rser=10m >SYMBOL cap 0 256 R0 >SYMATTR InstName C2 >SYMATTR Value 1� >SYMATTR SpiceLine Rser=10m >TEXT 224 152 Left 0 !K1 L1 L2 1 >TEXT -8 392 Left 0 !.tran 0 100m 5m >TEXT 128 296 Left 0 !.opt plotwinsize 0 > >- YD. That's nice. It's running pretty hard class C. Try this: C2 = 10 uF L2 = 0.25 uH That will move it to class A, with about 50 millivolts p-p drive at the emitter. That's more like what I had in mind originally. Vb is stiff at about +0.6, and Vc dips down to about -0.1, a little below Ve, sucking a brief blip of current out of the base cap. The sine wave is just slightly flattened on the bottom. It's useful to add a small resistor, like 1 milliohm, in the emitter so that you can probe the current. It's interesting. I measure the amplitude at the collector at 10.11 p-p, pretty close to 2*Vcc. ftp://jjlarkin.lmi.net/LC_YDx.gif John |