HP A Series - Section IV Principles of Operation; Overall Description

SECTION IV
PRINCIPLES OF OPERATION
4-1 OVERALL DESCRIPTION
4-2 Figure 4-1 is a simpiified schematic of the power
supply indicating ail of its major circuits. Except for
minor variations {discussed later in Section IV) the
Hewlett-Packard modular supplies covered by this
manual are as shown in Figure 4-1. Notice that each
stage of the supply has been designated according to
function. These functional designations also appear on
the applicable schematic at the rear of the manual so
that both diagrams can be correlated.
4-3 The ac input voltage is reduced to the proper
level by the power transformer and fed to the rectifier-
filter where it is converted to raw (unregulated) dc. The
raw dc voltage is adjusted by the series regulator so that
a regulated, constant voltage is available across the out¬
put terminals of the supply.
4-4 The series regulator, part of a feedback loop,
alters its conduction in accordance with the feedback
control signals obtained from the driver. The driver,
in turn, is controlled by feedback signals originated in
4-1