Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



WTB High Voltage Capacitor

Anthony P

Active member
LPF Site Supporter
Joined
Oct 7, 2018
Messages
310
Points
43
I am revisiting the Scientic American Flash-lamp Pumped Dye Laser, and am searching for a suitable capacitor. In the past, Condenser Products has custom made anything I could imagine. They can not help this time, nor can e-bay et.al. This is what I am looking for:

20KV or more
As close to 1microfarad as possible
MUST be low inductance type, fast discharge

At this point I am considering a homemade cap. My N2 project rquired the construction of a 12"x18"x.010" copper sheet cap. It clocks in at 10nF. 100 layers should do the trick. I would much rather just fork out the dough to buy buy one, but I can't find one. A home-made 100 layer cap is a little nuts, but it would not be a real laser project if there wasn't some degree of insanity involved.
 



paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
15,850
Points
113
If you must build your own capacitor, look into dielectrics. They can increase your capacitance without increasing plate size. 1 uF at 20 kV is a bit unusual.
 

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
11,640
Points
113
I have used oil filled capacitors in series to increase the voltage, of course the capacitance is reduced that way, but find high enough ones and 20 KV should not be too difficult to reach and still have one microfarad. You may want balancing resistors between them though.

Edit: Two of these, if you can find them will give 1 uF at 20 KV:


This same seller has a 1 uF 10 KV oil filled capacitor listed too, but since he has only one, I don't think you would want to use it as the capacitance would only be .666 uF when in series with 2 uF. If he had two, you could series parallel those two with the larger one and get your 2 uF.

You could buy that one 2 uF and then these five capacitors to series together with it, since they are 35 uF each, maybe achieve what you want:


You probably already know this formula well, but just in case: Capacitors connected in series will have a lower total capacitance than any single one in the circuit. If you have not seen it, click to see the formula.

 
Last edited:

Anthony P

Active member
LPF Site Supporter
Joined
Oct 7, 2018
Messages
310
Points
43
Alaskan: Thank you so much for your help. I will look up the inductance on those caps to see if they are suitable. BTW, like the new avatar.

Paul: I am going to do some bench tests on mylar sheets this weekend. It has a very high dielectric strength and is readily available in a variety of thicknesses. It apparently has some use in quilting and other art stuff.
 




Top