HP 6960A - Principles of Operation; Overall Block Diagram; Circuit Description

Model 6960 A
SECTION IV
PRINCIPLES OF OPERATION
4-1 Overall Block Diagram
Section IV
4-2 As shown in Figure 4-1 the power transformer feeds two fullwave rectifiers. The
rectified AC is filtered and controlled by a series regulator. The two built in
series
regulators can be operated either in series or parallel depending upon the
selected range of the push button switch and are controlled from the error
ampl ifier man itoring the output vol tage of the supply.
The voltage monitoring error amplifier senses any change in the output voltage
compared to a reference voltage. The output of the amplifier causes the resistance of
the series regulator to be varied in such a way as to keep the output voltage constant.
The programming current, determined by the reference voltage and the series resistor
R
35, flows mainly through the VOLTAGE ADJUST potentiometer R 40. The product of
the programming current and the value of R 40 equals the output voltage.
4-3 Circuit Description
4-4 The schematic diagram (Fig 5-4) shows all details of the circuit. Power trans-
former is shown to consist of three secondary windings of which the upper two
are the main sources of DC power, while the lower supplies the reference and
auxiliary voltage circuit. Rectifier bridges CR 3 to CR 6 and CR 7 to CR 10
are coupled by R 1. Fi Itering is provided by capacitors C2 and C3. Resistors
POWER
LINE
SUPPLY SUPPLY
OUTPU
RECTIFIERS
REGULATORS
>-to
POWER
ERROR
TRANSFORMER
AMPLIFIER
REFERENCE REFERENCE
RECTIFIERS REGULATORS
T
Fig. 4 - 1 Block Diogram
4-1