-----Original Message-----
From: Glenn McNeil <vk4tzl@bigpond.com>
To: amps@contesting.com <amps@contesting.com>
To: <amps@contesting.com>
Date: 16 May 2001 01:05
Subject: [AMPS] Voltage Doublers
>
>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,
YES big C means big peak currents. Visit www.duncanamps.com and download
their free PSU analyser software. You can look at the peak current in the
transformer, diodes and capacitors. It will also calculate the rms current
values so you can calculate dissipation and check capacitor ripple current
ratings.
>and will this make the supply too "stiff" if things go bang
not if you include a series glitch resistor between the stack and the PA.
Steve
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