John Larkin's LC oscillator
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From: Robert Baer on 11 Jun 2010 14:08 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!
From: John Larkin on 11 Jun 2010 15:28 On Fri, 11 Jun 2010 09:49:47 -0700, BlindBaby <BlindMelonChitlin(a)wellnevergetthatonethealbumcover.org> wrote: >On Fri, 11 Jun 2010 09:14:34 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Fri, 11 Jun 2010 09:09:29 -0700, BlindBaby >><BlindMelonChitlin(a)wellnevergetthatonethealbumcover.org> wrote: >> >>>On Fri, 11 Jun 2010 08:37:43 -0700, John Larkin >>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>>On Fri, 11 Jun 2010 17:15:50 +0200, Jeroen Belleman >>>><jeroen(a)nospam.please> wrote: >>>> >>>>>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. >>>>> >>>>>Jeroen Belleman >>>> >>>> >>>>Sloman is our resident squegging expert. >>>> >>>>John >>> >>> >>> We should take a poll as to what attribute you are an expert in. >>> >>> I don't think it would result in the same determination that you >>>obviously think it would. >> >>Do you know what squegging means? Tell us. > > I have characterized a lot of oscillator circuits at the bench, John. >Remember... power supplies... That was years ago. Now it is what the >power supplies power. Still lots of oscillators though. > >> >>There are maybe two usages, both electronic, > > I have very little faith in your word derivative/origin declarations, >John. That is aside from the fact that I am familiar with the word. >Remember? I work in this industry. > >> but one of them is >>obscure, > > Perhaps only in your thinking. > >> and the other is even more obscure. > > Certainly only in your thinking. Lotta munbling. What does it mean? What causes it? John
From: John Larkin on 11 Jun 2010 15:33 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. John
From: John Larkin on 11 Jun 2010 15:34 On Fri, 11 Jun 2010 11:56:27 -0500, John Fields <jfields(a)austininstruments.com> wrote: >On Fri, 11 Jun 2010 07:47:19 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Fri, 11 Jun 2010 07:02:44 -0500, "Tim Williams" >><tmoranwms(a)charter.net> wrote: >> >>>"Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in >>>message news:1q3316tr0ak2u8rdhr974agci3svmobtjo(a)4ax.com... >>>> Isn't there some young buck out there who can analyze circuits ?:-( >>> >>>Me? >>> >>>Go do it yourself Jim. >>> >>>Tim >> >>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. > >--- >What a lying, insolent wretch you are. > >You don't even have the good grace to place component values on the >sketch and here, after I've gone to all the trouble of prettying it up >so it'll run at an audible frequency, simulating it, and even getting >a .wav file so the gong sound can be heard, you have nothing but lies, >insults, and, of course, no acknowledgement of the work and time spent >on your behalf. What's your hourly rate? Send me a bill. John
From: John Larkin on 11 Jun 2010 15:37
On Fri, 11 Jun 2010 10:50:15 -0700, Robert Baer <robertbaer(a)localnet.com> wrote: >..and if the drive parameters can be tweaked for minimum losses like >that, byt still have sufficient gain to start oscillations, then the >linearity and purity would then be maximized. :-) John |