Re: My NE-2 Relaxation Oscillator is Too Relaxed ???

<jalbers@[EMAIL PROTECTED]
> wrote in message
news:2f8acf53-1cda-424c-9073-6706a1eb55ac@[EMAIL PROTECTED]
> I am experimenting with a relaxation oscillator circuit consisting of
> a NE-2 bulb wired parallel to a capacitor and this pair is wired in
> series with a resistor and connected across a 150 V DC power source (a
> bunch of DC wallwarts connected in series).  The resistor is variable
> 0-1 Meg Ohm, the capacitor is a 1uF electrolytic rated at 160V.  I
> don't have any capacitors on hand with a higher working voltage.
>
> The circuit seems to work.  I can get the bulb to blink around 3 times
> a second but I am wanting a higher flash rate and I am not getting
> it.  Lowering the resistance makes the bulb turn on continuously.  I
> don't think that the bulb is fla****ng faster than the eye can
> distinguish.  I conneded the circuit to an oscilliscope and when the
> bulfb is visually fla****ng I see the RC discharge curve but lowering R
> until the bulf truns on continuously pretty much produces a flat line
> on the scope.
>
> I was expecting to maybe be able to get around 2-100 hz with a NE-2
> relaxation oscillator.  Is this possible or am I expecting too much
> from this type of circuit?  And if so, why?
>
> Any help would be greatly appreciated.  Thanks

As mentioned above, use a much smaller capacitor. Also, never allow the
resistance to go near zero ohms as this can burn out the NE-2.

The Neon lamp is a negative resistance device. To oscillate it has to stay
in the negative resistance region. The pot is a positive or normal
resistor.
If it's value is adjusted too low, the overall combination resistance
becomes positive, oscillation stops and the lamp turns full on. That's
what
you are observing. Keep the resistor value high and the capacitor small.