HP 8112A Operating, Programming And Servicing Manual page 191

Servicing the Power Supply
Theory of Operation
Introduction
Line Voltage Selector
and Transformer
Bridge Rectifiers and
:Regulators
The HP 8 1 1 2A power supply unit occupies part of the main
board Al and consists of the following four parts, as shown in
Figure 1 0.2- 1 :
•
Line voltage selector and transformer
•
Voltage rectifi e rs and regulators
•
Voltage and current sensing circuits
•
Power-down detection circuit
Lil\E
SELECT
Figµre 1 0.2-1 . Power Supply block diagram
Refer to Figure 1 0.2-2. The line-voltage selector-switches, S2 and
S3, connect the incoming line-voltage lines to an appropriate pair of
transformer inputs. The transformer provides six ac outputs and an
earth line to the bridge rectifiers.
There are three bridge rectifiers, all modular and therefore
replaceable:
Servicing the Power Supply 1 0.2-1
1 0 . 2