CONTROL CIRCUITS

TM 11-5820-765-34

ACTION:

Manually adjust dc voltage adjust R4.

Resistors

R4,

change

setting.

Control circuitry in PC101(A1) senses change.

RESULTS:

Output voltage changes proportionally.

RESISTOR

FUNCTIONS:

R4 adjusts output voltage.

R8 adjusts voltage range.

1-12. CONTROL CIRCUITS

CIRCUIT

CARD

ASSEMBLY

PC101(A1):

Controls

power

supply

operation.

Senses voltage changes in ac input, dc output circuits.

Controls operation of voltage regulation, overvoltage circuits.

Derives power from two secondary windings on transformer T1.

V O L T A G E REGULATION CONTROL

PC101(A1) CONNECTS TO:

Silicon controlled rectifier SCR1(Q1).

Power supply's final dc output voltage.

NOTE

SCR1(Q1) regulates dc output voltage.

ACTION:

PC101 (A1) applies signal to SCR1 (Q1) gate.

SCR1(Q1) fires, conducts current after receiving signal.

Timing of control gate signal appears on gate.

TIMING:

Timing of control gate signal depends on value of output voltage fed to PC101(A1).

IF: Do output voltage increases

THEN: Time constants in PC101(A1) delay firing SCR1(Q1)

S O : SCR1(Q1) fires later in half-cycle

WHICH: Reduces output voltage

This restores output voltage to proper value.

IF: Do output voltage decreases

THEN: SCR1(Q1) fires early

WHICH: Raises voltage to proper value.

First Power Supply to PC101(A1)

POWER:

Plus and minus 20 volts.

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