I need to build a compact transformerless high voltage supply that will run off of 120VAC mains and produce at least 2000-4000 (AC or DC) volts with very low current. I figure what would be best is the "Walton-Cockroft voltage multiplier"
How many capacitors (and what type, size, ect) would I have to use for this to work?
TIA
Roughly 60 capacitors, say 10 uF each, and 60 diodes... it sure won't be "compact."
John
See
Page 32 - Generates 7.5kV DC negative, 400uA.
EXCELLENT link Homer. Thanks.
What size cap depends on how much power you want.
Capacitor voltage is established by the input voltage to the chain.
The URL you list, has the formula
Eout = 2n*Epk - VDrop .... VDrop=0 under no load
Voltage out, equals, 2 times the number of stages, and voltage peak of the input. (sine wave 120 VAC, times 1.4142 equals 170 Volts peak)
You would need 12 stages to get 4 KV out and each stage consists of two diodes and two capacitors.
The output of a Cockroft Walton is DC . . . always.
There are variations in the design to give full wave output with twice the parts for twice the power.
The bigger the size of the caps, the more output power and current.
Ripple increases substantially when you try to pull off power, so CW multipliers are used for low current applications, like ionizers, loading the belts of Van De Graf machines with electrons, in TV sets to provide acceleration voltage, bug zappers, charging up caps to high voltages etc..
The higher the frequency the more power you can get out of a given number of stages . . .
Charge a cap with one and you could conceivably electrocute yourself with it. Connect the side shown grounded in the first schematic to the AC hot wire and you could electrocute yourself with 120 volts.
An ionizing potential of ~10KV+ will charge objects near it with an electrostatic charge - causes static shocks if you are insulated from ground and near one spitting out ions, in a dry area.
-- ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =----
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.