30-10-2015, 05:17 PM
(30-10-2015, 12:32 AM)AlanBeckett Wrote: Morning Nick.
It doesn't matter which Diagram you use but your Diodes are backwards. 'Conventional Current' flows from the Anodes to the Filament so they should 'Point' in that direction.
Transformer Windings don't like being left floating so it's best to give them a bit of Load.
Alan
Good point that, Alan. Funny enough I'd done my own post before I then noticed the matter of load has been raised by you here. Personally I did all my own testing with no load on the transformer although, yes, it does make sense to consider the load factor. One thing I find a bit unavoidable is when, on testing a new set for a trial, you may wind up with lit filaments but no H.T. or anode load (because the H.T. supply had a fault). That worried me when it happened as I feared it would have damaged my output tube. Luckily it didn't but probably didn't do it any good either.
The golden rule I learned on rectifier flow:
AC supply braided wire from transformer to tube anode blocks the negative cycles. Only + cycles pass and appear as a voltage (pulse) at the cathode. That is, cathode is the + pulse. To clarify I tested this on both A.C. setting on a digital meter and on D.C. Only D.C. showed the high cathode voltage with reference to chassis.
This cathode wire will go to the H.T. can +terminal.
Works the same with silicon. Transformer leads connect to anodes and output in a DC ripple at the cathode.
Note, I refer to voltage as the electron current always flows from cathode to anode (heated filament free electron cloud attracted to anode H.T.)
