[AMPS] Voltage Doublers

Glenn McNeil vk4tzl@bigpond.com
Wed, 16 May 2001 09:50:59 +1000

A few questions about voltage doublers. I'm building a single tube 4CX250R for 70cm using a voltage doubler 
supply. This is my first attempt at FWD supplies.

I have a transformer with about 750vac secondary, 12ohms dc resistance. I'm planning on using IN5408 diodes and 
a string of electro's. 

(1) I can either use 5 x 190 uf 400vdc caps in each side of the stack, second hand, or 5 x 1500 uf 250vdc caps 
which are new but will give a much greater overall capacity. Is there such a thing as too much capacity in the stack, 
and will this make the supply too "stiff" if things go bang

(2) Is modern practice to still put C and R across each individual diode in the rectifier stack.

(3) Is it good practice to place a diode across each cap in the stack, cathode towards the + side, for reverse current 

All advice gratefully received.



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