simple cockcroft-walton voltage multiplier

Discussion in 'The Projects Forum' started by Guy_1024, Mar 4, 2015.

1. Guy_1024 Thread Starter New Member

Sep 21, 2014
2
0
Hi everybody,
So I tried to build a simple voltage multiplier and it works perfectly fine, the output is exactly as I predicted.
The problem pops up whenever I try to put a load on it. The output voltage gets down the a third of what it should be. In this case my load is a single electrolytic capacitor - 360V and 2000uF.
The multiplier has 5 stages and the capacitors are 400V and 100uF.
Can somebody please explain to me why does the output voltage drops whenever I connect the big capacitor?
How can I charge this capacitor to about 300V otherwise?
This is my first ever electronics project so my knowledge on the subject is quite low but hopefully you guys can help me.
Thank you very much!

2. wayneh Expert

Sep 9, 2010
12,396
3,246
Schematic? It's a common feature of voltage multipliers that they have rapidly declining current capability as the voltage multiplier factor increases. With 5 stages, it will be next to nothing. Still, the voltage should slowly rise on your capacitor unless it is leaking more than what's coming in.

3. wayneh Expert

Sep 9, 2010
12,396
3,246
Are those all electrolytic capacitors?

4. alfacliff Well-Known Member

Dec 13, 2013
2,449
428
have you waited for the large cap to charge?

5. Guy_1024 Thread Starter New Member

Sep 21, 2014
2
0
Yes sir, all the caps are electrolytic caps.

I have waited about half a minute and nothing moved.

There is a schematic (hopefully it is clear enough) :

Thank you everybody for your super fast replies!!!

6. #12 Expert

Nov 30, 2010
16,705
7,355
I calculate 283 volts. That isn't very far from 290 volts.
The capacitors add up to 159 ohms, but that shouldn't stop everything.
I guess you just have to attach the load and go through measuring each junction to see where the voltage falls apart.
This is what your circuit looks like to an electron.

• Impedance in a voltage doubler.png
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Last edited: Mar 4, 2015