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.

Check out the tube data sheets, available on several websites. If you
need urls, I can dig them up. The RCA HB-3 books are online for sure.

Do the formulas for solid state rectifiers apply??

Not directly, because tube rectifiers tend to have more drop than
silicon. Different types have different drop, too, and it depends on
the current load. An important concern in setups where the current
draw varies (such as CW transmitters) is the voltage regulation of the
supply from minimum to maximum load. Different types of rectifier tube
have different regulation performance.

As a limiting case, with a full wave center tap rectifier using a
transformer giving Vt volts on either side of center tap, the
*maximum* voltage you will get is:

1.4 * Vt (capacitor input filter)
0.9 * Vt (choke input filter)

In real-life applications, the output voltage will be less.

The 6X5 is good up to 70 mA, but has relatively high voltage drop and
relatively poor regulation. The 5Y3 is better, the 5V4 better still,
and the 5U4 even better. The ultimate in tube rectifiers are the
mercury vapor types, but that's a subject for another post.

What transformer do you have available, and what is the application?

btw, I have found that an input capacitor of 40uf is fine with the 5Y3
and larger rectifiers.

73 de Jim, N2EY