John Larkin's LC oscillator
in [Design]
|
Prev: Skybuck's Universal Code Version 6 (The Fast Version)
Next: CCt to converter 24Vdc signals to 12Vdc signals
From: Jasen Betts on 12 Jun 2010 04:39 On 2010-06-11, BlindBaby <BlindMelonChitlin(a)wellnevergetthatonethealbumcover.org> wrote: > On Fri, 11 Jun 2010 08:16:29 -0500, John Fields ><jfields(a)austininstruments.com> wrote: > .... >>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. Works fine here. version 4.07q --- news://freenews.netfront.net/ - complaints: news(a)netfront.net ---
From: Jasen Betts on 12 Jun 2010 04:51 On 2010-06-11, Robert Baer <robertbaer(a)localnet.com> wrote: > YD 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. >> >> 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. >> >> - YD. >> > In fact, it would be interesting to know how to "resonate" an > inductor that has a lot of (internal) resistance. add external negative resistance. --- news://freenews.netfront.net/ - complaints: news(a)netfront.net ---
From: John Larkin on 12 Jun 2010 10:57 On Sat, 12 Jun 2010 08:53:20 +0100, John Devereux <john(a)devereux.me.uk> wrote: >John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> writes: > >> 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: > >[...] > >> >> 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. > >Hi John, > >You don't need to add the the resistor. You can just measure the emitter >current by clicking on it! > I couldn't get that to work. Maybe my aim isn't good enough. John
From: Archimedes' Lever on 12 Jun 2010 11:04 On 12 Jun 2010 08:39:10 GMT, Jasen Betts <jasen(a)xnet.co.nz> wrote: >On 2010-06-11, BlindBaby <BlindMelonChitlin(a)wellnevergetthatonethealbumcover.org> wrote: >> On Fri, 11 Jun 2010 08:16:29 -0500, John Fields >><jfields(a)austininstruments.com> wrote: >> >... >>>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. > >Works fine here. version 4.07q > >--- news://freenews.netfront.net/ - complaints: news(a)netfront.net --- I chose the wrong extension to name the file with.
From: Archimedes' Lever on 12 Jun 2010 11:07
On Sat, 12 Jun 2010 20:31:02 +1000, Grant <omg(a)grrr.id.au> wrote: >On Fri, 11 Jun 2010 16:02:58 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Fri, 11 Jun 2010 15:37:52 -0700, BlindBaby >><BlindMelonChitlin(a)wellnevergetthatonethealbumcover.org> wrote: >> >>>On Sat, 12 Jun 2010 08:07:41 +1000, Grant <omg(a)grrr.id.au> wrote: >>> >>>>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: >>>> >>>>Sounds wonderful! There's so much I don't know about what LTSpice >>>>can do :( More examples that load and work as advertised, the better :) >>>> >>>>Grant. >>> >>> >>> LTSpiceIV just came out today! >>> >>>http://www.linear.com/designtools/software/switchercad.jsp >> >> >>I've been running 4.07 for a couple of weeks now. > >Mine updated itself a while back, just checked --> 4.07. > >Grant. 4.07 what. Mine is 4.07z They do auto-update, but not on every run. So, you may still have the one you loaded originally. |