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Old March 25th 04, 01:36 PM
Hans Summers
 
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"Uwe" wrote in message
...
I am looking for info regarding a simple power supply with a full wave
rectifier (I got a 6X5).
Mainly I need to know the 'to be expected output voltage' (capacitor
filter)for any input. I don't have info on that.
Do the formulas for solid state rectifiers apply??


See http://www.hanssummers.com/radio/glowbug/psu/index.htm

I use a GZ33 rectifier valve, followed by pi-filter containing a 16uF
capacitor, 5H choke, and 400uF capacitor.

I am no expert but from what I have learnt the following points are
important:

1. The first capacitor should be relatively low value (my 16uF seemed about
right). This capacitor should also be a very sturdy type, so that it is
unlikely to fail. A less robust electrolytic in this location might fail and
short out, destroying the rectifier valve in the process. Therefore I use an
overspecified bipolar capacitor in this location.

2. Don't forget a bleeder resistor across the output, essential for your
safety! This will discharge the capacitors within some seconds of switching
off, making it safe to work on your equipment.

3. Small resistors (I use 55 ohm) in series with the rectifier anodes are
needed to protect the valve from switch-on surge currents.

I also use a VR150/30 gas filled regulator valve to produce a 150V regulated
output in addition to the 350V HT.

73

Hans G0UPL
http://www.HansSummers.com