John Larkin's LC oscillator
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From: BlindBaby on 12 Jun 2010 20:22 On Sat, 12 Jun 2010 18:45:44 -0500, John Fields <jfields(a)austininstruments.com> wrote: >>And if you play with >>the base bias resistor, you can make something that looks fairly >>chaotic, sort of ratty like a superregen. > >--- >Well, of course you can. > >So what? That is John, 'squegging' on the group.
From: YD on 13 Jun 2010 00:28 Late at night, by candle light, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> penned this immortal opus: >On Sat, 12 Jun 2010 19:38:42 -0300, YD <ydtechHAT(a)techie.com> wrote: > >>Late at night, by candle light, John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> penned this immortal >>opus: >> >>>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 >>> >> >>Just hover the pointer over the terminal until it looks like a >>clampmeter. One of those things I found quite by accident, and nicely >>surprised. >> > >I know that, but I had a hard time hitting the emitter current. The >resistor is a bigger target. Maybe I should buy more pixels or >something. > >John Yeah, the "sensitive" area is quite small, apparently only a few pixels across. Another way is to use a 0 V source instead of the resistor, then you can be sure of polarity too. I recall doing that in some ancient SPICE from the DOS daze. - YD. -- Remove HAT if replying by mail.
From: JosephKK on 13 Jun 2010 02:41 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! :-) > The sim runs but i cannot find the wave file. Where do you think it gets put when in wine? >--- >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
From: BlindBaby on 13 Jun 2010 04:24 On Sat, 12 Jun 2010 23:41:24 -0700, "JosephKK"<quiettechblue(a)yahoo.com> 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! :-) >> > >The sim runs but i cannot find the wave file. Where do you think it gets >put when in wine? > That depends on how you set your wine up. Learn to snip better.
From: Jasen Betts on 13 Jun 2010 05:59
On 2010-06-12, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > On Sat, 12 Jun 2010 08:53:20 +0100, John Devereux ><john(a)devereux.me.uk> wrote: > >>> 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. After running the sim point at the component you want to see current through and the cursor should change to look like a black clamp meter instead of a red probe. It only works on components, for devices with more than 2 terminals you have to get the joint between the dark blue component and the light blue interconnect wiring. Or you can hold the [Alt] key down and it'll do current instead of voltage on the wires, and a thermometer looking thing (which I haven't figured out how to use) on the components --- news://freenews.netfront.net/ - complaints: news(a)netfront.net --- |