Re: AC resonance circuit with DC electrolytic capacitors? (resonating, res...

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Mddeming@xxxxxxx 



    I think that the heating/cooling response curve of the bulb may 
be a couple of orders of magnitude too slow for anything except the 
lowest of oscillations. I seem to remember a kid in my class back ca 
1960 who tried, unsuccessfully, to build a filament-modulated 
amplifier. If one could tie down the response curve time constant for 
the bulb filament, in might make an interesting simulation.

Matt D.

In a message dated 3/11/07 10:42:37 P.M. Eastern Standard Time, 
tesla@xxxxxxxxxx writes:
Original poster: Ed Phillips <evp@xxxxxxxxxxx>

Tesla list wrote:

>Original poster: "Antonio Carlos M. de Queiroz" <acmdq@xxxxxxxxxx>
>
>Tesla list wrote:
>
>>Original poster: "S&JY" <youngs@xxxxxxxxx>
>>
>>Not really.  As the lamp filament heats and cools, it causes filament
>>resistance to change, which slightly changes the resonant frequency of the
>>RLC circuit, which causes the current in the RLC to vary, which causes the
>>lamp to dim and brighten, which causes the filament resistance to vary,
>>which ... etc.
>
>Something strange in this...
>If the capacitor, inductor, and lamp are in series, the frequency
>where there is maximum
>voltage over the lamp does not depend on its resistance. Maybe with
>a different connection
>this can work. With the lamp in parallel with the capacitor, and
>adding some resistance in
>the inductor,  the circuit has a structure similar to a well known
>chaotic circuit, and may
>work as a chaotic resonator. (Something to verify.)
>
>Antonio Carlos M. de Queiroz

  This effect is probably due to saturation of the inductor core.
Fairly easy to duplicate with the right circuit constants.  Increase
in current raises the filament temperature and drops the fraction of
the voltage across the inductor.

Ed






----------
AOL now offers free email to everyone. Find out more about what's 
free from AOL at <http://www.aol.com?ncid=AOLAOF00020000000339>AOL.com.