With the design suggested by Havun, it seems like I don’t even need a transformer to reach 3kV. I assume the center tap from the step up would be connected to the ground of this circuit, and then the positive to the diaphragm.
To adjust the output voltage, I would just have to move the positive to a lower step on the multiplier ladder. Then a quick Google told me it isn‘t ideal to connect 115VAC directly to a breadboard circuit due to the risk of accidentally touching. Though I believe it is fine electronically, and I will be very careful handling it once live. Thank you for the clear schematic!
PS.
Decided on a generic screw on solder IEC C14 connector, for now I won’t be looking at any DC-DC bias supply.
To adjust the output voltage, I would just have to move the positive to a lower step on the multiplier ladder. Then a quick Google told me it isn‘t ideal to connect 115VAC directly to a breadboard circuit due to the risk of accidentally touching. Though I believe it is fine electronically, and I will be very careful handling it once live. Thank you for the clear schematic!
PS.
Decided on a generic screw on solder IEC C14 connector, for now I won’t be looking at any DC-DC bias supply.
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Since I don't have a HV probe for my DVM, I haven't measured the actual voltage output from my bias supply circuit. The small transformer in front of the ladder is rated at 115VAC in and 230VAC out, at its rated load. Assuming 230 volts out of the transformer, peak voltage at the end of the ladder would be 3.2KV. However, I measured the output at the transformer at 315 volts, while not under load. The actual load is probably less than the transformer's rated load, so I suspect the actual voltage at the end of the ladder is significantly higher than 3.2kV.
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So this means that it is very desirable for me to use the transformerless schematic Havun shared since I don’t need the output to be that high at all. And considering how high the resistance on the diaphragm is, my understanding is that it draws very little current, and therefore put a small load on the transformer. In that sense, maybe your transformer was not under too much load at all and was able to constantly output a high bias voltage. Apologies if what I said didn’t make sense.
That is what I have hypothesized! In a way, over drawing the circuit, due to whatever freak accident, would over draw the transformer and stop things there. Perhaps I will look at a $20 transformer and use even less multiplication. Thank you!
My bias supply is simple, cheap and reliable. I think it would work fine for your project if you omit the last 4 capacitors and diodes, to drop the voltage down.
Here's my parts list for two bias supplies, just reduce the number of diodes & caps to fit your need:
Here's my parts list for two bias supplies, just reduce the number of diodes & caps to fit your need:
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