Hello all,
I am attempting to build a simple sine wave generator that operates at 200kHz with an amplitude of 3000v RMS and a current of 10 mA. Any suggestions? Are there any additional considerations due to the high voltage? Thanks for any help you can provide!

 

Don't put your lips on it!!

On a more serious note -- what is the application for such a device and are there any additional constraints you would care to mention. Safety is a primary issue on this forum and you need to convince us that this device does not pose unacceptable risks in its construction, operation, and application.

 

How accurately does the sinewave have to be?

 

Hi,
Thanks for your responses. The sine wave doesn't have to be all that accurate. It will be used to roughly mimic a device that is commonly used at my workplace and will be used in product testing. Safety is of course a primary issue for me as well so that is why I'm seeking advice rather than just building something and watching it blow up or melt down

As per other constraints, there aren't really too many except that it obviously needs to be safe and hopefully not overheat and should be able to work when plugged into a typical wall socket. Also, smaller is probably better but not critically important.

 

You can build a low power sinewave oscillator to get a 200 kHz source. You can use a transformer to raise the voltage by a factor of 1000, while cutting the current by the same factor of 1000. So imagine we start with a 3VAC signal and we want a transformer the will change it to 3000VAC. To get 10 mA out how much will we have to put in? Answer 10 Amperes.

At high voltages and currents you need beefier components with thicker insulation, and more careful layout and fabrication.

What kind of power sources are available for this device?

 

Have you noticed...any question that has the word, "simple" in it take at least 30 posts to resolve?

 

Have you noticed...any question that has the word, "simple" in it take at least 30 posts to resolve?

Yes. Perhaps the proper term would be "as simple as possible".

To the OP: Does the output drive a fixed or varying load?

 

The power will have to be supplied by a standard (120V, 60Hz) wall outlet. The output will be a testing circuit that has a fixed input impedance of around 100 MegaOhms. So, this thing (hopefully) isn't going to draw much current nor power. I'm hoping for an output power of a couple watts or less.

Thanks again for your help!!

 

The power will have to be supplied by a standard (120V, 60Hz) wall outlet. The output will be a testing circuit that has a fixed input impedance of around 100 MegaOhms. So, this thing (hopefully) isn't going to draw much current nor power. I'm hoping for an output power of a couple watts or less.

An output of 10mA at 3000V would require a 30VA capability. What is the load capacitance?

 

Hi all. Thanks so much for your help and sorry for my lag in replying. I'll be much quicker from now on...

An output of 10mA at 3000V would require a 30VA capability. What is the load capacitance?

As I realized too late, it's obviously silly of me to have posted those power and resistance values given my stated voltage. What I really mean to say is that the generator needn't have a high output current/power and I just threw out 10mA as a rough number.

The load is a digital testing circuit prefaced by an optoisolator and rectifier, along with a large resistor that I will use as a voltage divider to get the voltage down to acceptable levels for that circuit. So, I can pick the values of the large R to suit whatever output power is ideal.

The only important design constraints are:

3000V, 200kHz

Really, I need suggestions on how to create the initial waveform and then amplify it to the desired voltage. I have some ideas such as using a Colpitts type oscillator and then a transformer or Op-amp to amplify it but since I've never built one of these things, I don't know whether this is the best way and I am hoping for suggestions on how to do this optimally and safely.

Thanks again for your responses!