Power transformer question in vacuum tube circuit
While one half of AC period, two bridge rectifier diodes are open (see effective chematic below). So, one end of secondary is connected to ground and another - to 300 V output capacitor. At the same time, center tap produces half of full secondary voltage.

On another half of AC period, picture is almost the same, just anoter two diodes of bridge rectifier are opened.

So, center tap produces fully rectidied waveform with half of full secondary amplitude.







simulate this circuit &ndash; Schematic created using CircuitLab