High Voltage Rectifiers and Output

The high-voltage transformer T1420 has two output windings. One winding provides filament voltage for the cathode-ray tube. The filament voltage can be supplied from the High-Voltage Supply, since the cathode-ray tube has a very low filament current drain. The cathode and filament of the CRT are connected together to elevate the filament and prevent cathode-to-filament breakdown. One high-voltage winding provides both the negative cathode potential and the positive anode accelerating voltage. The CRT grid bias voltage is derived by a DC restorer circuit that uses a sample of the signal in the high-voltage winding in conjunction with DC levels supplied by the Z-Axis Amplifier and the negative cathode potential.

The positive accelerating potential is supplied by High Voltage Multiplier U1432. Regulated output voltage is approximately +15,500 volts. The negative cathode potential is supplied by half-wave rectifier CR1241. Voltage output is —2450 volts. Voltage variations in this supply are monitored by the High-Voltage Regulator circuit to provide a regulated high-voltage output.

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