Agilent Technologies E3632A - Manual (Page 144)

Chapter 7 Tutorial
Overview of Agilent E3632A Operation
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7
Overview of Agilent E3632A Operation
Series regulated power supplies were introduced many years ago and are still
used extensively today. The basic design technique, which has not changed
over the years, consists of placing a control element in series with the rectifier
and load device. Figure 7-1 shows a simplified schematic of a series regulated
supply with the series element depicted as a variable resistor. Feedback
control circuits continuously monitor the output and adjust the series
resistance to maintain a constant output voltage. Because the variable
resistance of Figure 7-1 is actually one or more power transistor operating in
the linear (class A) mode, supplies with this type of regulator are often called
linear power supplies. Linear power supplies have many advantages and
usually provide the simplest most effective means of satisfying high
performance and low power requirements.
Figure 7-1. Diagram of Simple Series Power Supply with Tap Selection
To keep the voltage across the series resistance low, some supplies use
preregulation before the rectifier bridge. Figure 7-1 shows a controlled
transformer tap as used in the Agilent E3632A. This is one of several techniques
using semiconductors for preregulation to reduce the power dissipated across
the series element.