KEPCO JQE 150-1.5MVPY-26956 Half Rack - Manual (Page 45)

JQE SPECIAL SVC 081111 5-5/(4-6 Blank)
tered by A1C2. A current regulator stage, A1Q3, followed by a string of zener diodes, A1CR10
to A1CR13, provides the operating voltage for the amplifiers, ±13.5V and ±6.2V reference volt-
ages.
PRE-DRIVER COLLECTOR SUPPLY. A full wave rectified (A1CR6) and capacitor filtered
(A1C7) supply is derived from a secondary winding on T202. It delivers collector voltage to the
pre-driver stage A1Q2.
CONSTANT CURRENT RETURN SUPPLY. This full-wave rectified auxiliary supply is derived
from the winding of the auxiliary power transformer. Rectified by A1CR1 and filtered by A1C1,
constant current is applied to the base of the pass transistors (via the constant current generator
stage A1Q1, thus insuring the control of the Pass-Element for zero output voltage and/or zero
output current.
5.2.8 METERING CIRCUIT
Both output voltage and output current are monitored by dual range front panel meters (M101,
M102). While the output voltage is measured directly across error sensing terminals 1 (–S) and
5 (+S) of terminal block TB501, the output current is measured indirectly as a voltage drop
across the current sensing resistor (R203).