11-04-2017, 09:34 AM
If you consider your primary to be identical to the HT secondary of a mains transformer, it might help the understanding.
If you have, say, a 250-0-250 volt winding, it can also be looked at (or even used) as a single 500V winding with a centre tap so the two halves must be wound in the same direction for that to be possible.
In normal use, the centre tap will be the common, earthed, point. Then, on one half cycle of the mains input, one end of the secondary will go positive relative to the centre tap and the other end will go negative. On the second half cycle, the polarities will reverse.
An output transformer works in exactly the same way as a mains transformer but in reverse. Because of the phase splitting arrangement feeding the output valves, the anode current through one valve will be increasing whilst the current through the other valve is reducing - ie: like the HT winding on the mains transformer, the current flowing in each half of the primary and hence the voltages induced across the two halves relative to the common centre point which, in this case is connected to HT+, will be in anti-phase exactly the same as before with the situation reversing on each half cycle.
Does that help?
If you have, say, a 250-0-250 volt winding, it can also be looked at (or even used) as a single 500V winding with a centre tap so the two halves must be wound in the same direction for that to be possible.
In normal use, the centre tap will be the common, earthed, point. Then, on one half cycle of the mains input, one end of the secondary will go positive relative to the centre tap and the other end will go negative. On the second half cycle, the polarities will reverse.
An output transformer works in exactly the same way as a mains transformer but in reverse. Because of the phase splitting arrangement feeding the output valves, the anode current through one valve will be increasing whilst the current through the other valve is reducing - ie: like the HT winding on the mains transformer, the current flowing in each half of the primary and hence the voltages induced across the two halves relative to the common centre point which, in this case is connected to HT+, will be in anti-phase exactly the same as before with the situation reversing on each half cycle.
Does that help?
