# 15kDCV low current power supply?

#### freewill

Mar 8, 2023
2
Looking for some help, please. I don't know much about electronics - studying hard at the moment.

I need to make as cheaply and simply as possible a 15kV (or thereabouts) DC power supply with low output current - ideally around 20-25 microA.
(The application is boring; if you know the answer to the power supply, you'll probably guess its application. Please let's not have a thread about the application.)

A 3.7V 18650 battery should have enough juice, but I don't care too much about the input.

This thing is frustratingly close:

It outputs 15kV AC
The specs say output current is 0.4A, but of course that's not right, it must be 0.4mA.

I guess I can reduce the output current by replacing the resistor?

Is there a cheap and simple way to make a rectifier for the output?
Or a similar transformer with lower voltage output that I can add a voltage multiplier to?
Or any other kit or cheap prebuilt unit that gives around 15kDCV at around 20-25 microA?

Thanks, guys

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Feb 19, 2021
622

Possibly those ?

Regards, Dana.

#### freewill

Mar 8, 2023
2
No, that is the transformer I showed. I've scoured eBay and Ali already.

#### kellys_eye

Jun 25, 2010
6,043
In it's simplest possible form you could use an astable circuit driving the secondary of a small mains transformer (or a 7555 CMOS-device driving an audio push-pull output transformer or even a hand-wound ferrite transformer) and connect the primary output to a string of multipliers (diode/capacitor). A final set of series connected resistors can be calculated to limit the current you require. You could even tap the output and use the voltage as feedback to stabilise the output if that's what's required?

Back-of-a-fag-packet calculation assuming a 7555/audio transformer (type LT700)

https://www.esr.co.uk/shop/contents...ansformer,_Pri_1k2,_Sec_2_x_3R2_(LT-700).html

would mean a voltage multiplier of x10 to x15 (some experimentation required) - note, capacitor values shown are for a 1kHz source only, use larger values for low frequencies. The LT700 is good for up to 1 to 5kHz only though. Here's a schematic of an x8 multiplier. DC output of course.....

#### Bluejets

Oct 5, 2014
6,586
12v car ignition coil.....older kettering style perhaps.

#### ivak245

Jun 11, 2021
89
How about a cheap bug zapper? I'm not sure of the output voltage, but the "tennis racket" type are cheap enough to have a play with. They are usually powered by 2 "C" cells, so 1 X 18650 should fire it up OK.

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