[Tburke2]

I need a circuit that uses a 9v battery as the input and creates a 300hz, sinusoidal output at at least 500v, there will be no load connected. I've tried a Wien bridge oscillator but the signal gets distorted by the transformer I have connected (120v to 6.3v stepdown wired backwards ). Everything I try either can't push enough current through the transformer or creates way too high of a frequency. Any help is appreciated, thanks.

 

[Arouse1973]

Dare I ask why you want 500 Volts?
Adam

 

[Tburke2]

To trap a charged water droplet in an electric field

 

[Arouse1973]

Sounds interesting. Have a look at a Royer oscillator. I guess you understand this sort of high voltage is very dangerous. What experience do you have working with high voltages?
Adam

 

[Tburke2]

Thanks, I'll have a look. Well right now I'm using a neon sign transformer and a function generator but I'm trying to make it portable. The setup now is about 700v so I'd assume a battery powered setup wouldn't be able to source as much current and therefor be much safer.

 

[Arouse1973]

You don't need much current to kill yourself. A PP3 battery can produce enough current to kill you but the voltage is too low. Anything of such high voltage needs to be treated with respect.
Adam

 

[hevans1944]

You could try driving your step-down "filament" transformer in a resonant mode. Drive the low-voltage side with a square-wave oscillator and place a "tuning" capacitor, value TBD, across the secondary. Vary the frequency of the input to find the resonance frequency. Be careful to reduce the drive current as you approach resonance and determine how much voltage you get on the secondary using an oscilloscope and appropriate "high voltage" probe. The capacitor must of course be rated for the peak-to-peak output voltage. I would begin with 1 μF rated at 1 kV and see what you get. Might want to load the secondary with a five or ten watt power resistor in the 1000 to 10,000 ohm range to control the "Q" of the resonant tank. The 9V battery will discharge rather quickly. You should consider a low-voltage mains supply to run this rig.

 

[Colin Mitchell]

Try a Xenon circuit from a disposable camera. I'm not sure about the waveform
Or a $3.00 Electroluminescence driver. It works a 400Hz and is sinewave

 

[Tburke2]

I don't have a transformer that has the primary tapped and the Royer oscillator requires a saturatable core so I don't think I can wind my own.
I can get a nice sine wave when my transformer is resonant but it's too high frequency, I add more capacitance to lower the frequency and of course the gain decreases too.
I looked at the electroluminescent driver and I think it will work, I'll order one today.

 

[hevans1944]

Sounds like a plan! Post here again if you need more ideas.