FUNCTIONING OF EQUIPMENT
bias applied to the master passing transistors.
Within the master passing stage, there is a
circuit which senses the impedance across the
The input power is applied to the primary
master transistors. This sensing circuit will
sides of variable autotransformer (variac)
control the action of the slave controller cir-
T1 and to transformer T3 of the auxiliary pow-
cuitry. A change in the master passing im-
er supply. The secondary voltage of autotrans-
pedance will cause a change in the slave pass-
former T1 is applied to the primary side of
ing stage impedance. The design of the con-
main power rectifier transformer T2.
troller circuits till assure the safe operation of
The
secondary circuit of transformer T2 forms a
the passing transistor stages under dynamic
full-wave solid-state rectifier circuit with re-
operating conditions. To prevent thermal dis-
sistor-capacitor filtering. The positive side of
sipation troubles (runaway) in the passing and
the main rectifier is applied to a slave passing
control stages, a static protective bias is pro-
transistor stage which is in series with a mas-
vided by several independent rectifier cir-
ter passing transistor stage. The two tran-
cuits on the secondary side of auxiliary power
sistor stages act similar to vacuum tube pass.
supply transformer T3. This protective bias
ing stages of conventional regulated power
is distributed to the slave controller, the mas-
supplies. The series impedance of the two
ter controller, the slave passing stage, and the
passing stages serves as the main regulating
master passing stage. Although it is not ap-
function of the power supply. The negative
parent on figure 4-1, the main rectifier, the
side of the main power rectifier is connected
passing transistors, the Zener diode reference
to the negative end of the load termination. A
circuit, the regulated reference supply, and
Zener diode reference circuit is provided to
the load resistance form a bridge-type cir-
sense any changes in the output level of the
cuit. A bridge circuit is a practical method for
power supply. The output of the reference
reducing the load voltage to zero while main-
circuit will control the action of a master con-
taining the proper protective currents on pass-
ing stage transistors, Q1 through Q6.
troller unit which, in turn, will adjust the base
Power Supply PP-3940/G block diagram.
4-1
