B&K Precision 1745A - Manual - Manual (Page 20)

APPLICATIONS
GENERAL
These model power supplies have a very wide variety of
applications in electrical and electronics servicing, engineering
laboratories, manufacturing and testing facilities, schools, and
home hobbies. The power supply output is fully adjustable from 0
to 35 volts and 0 to 10 amps. This flexibility makes them suitable
for most applications requiring a dc power source.
ELECTRONICS SERVICING
Most electronics troubleshooting and repair is performed on a
test bench. This power supply can provide the dc power source to
operate a module or circuit board on the test bench when it is
removed from its parent equipment. It can be used to power
portable, battery-operated equipment and check the effect of low
battery voltage. It can power vehicular equipment such as tape
players, auto sound systems, CB radios, etc. on the test bench.
Most automobiles and other vehicles use 12-volt electrical
systems. Although the electrical system is normally referred to as
a 12-volt system, actual battery voltage when fully charged is
approximately 14 volts. The power supply may be set to 14 volts
for servicing equipment from vehicles with 12-volt electrical
systems. Some trucks use a 24-volt electrical system; bench
testing of equipment from these systems should be performed at
28 volts.
Some servicing applications require the injection of a variable
dc voltage for certain tests, such as checking the effect of AGC
bias in a television receiver. This requires an isolated dc power
supply, such as the Model 1743B.
The equipment being tested may contain its own power
supply and operate from ac power. A dc voltage may already
be present in the circuit. One polarity of the power supply
output is floated to an appropriate point in the circuit, such as
the emitter of a transistor. The other polarity of the power
supply output is then applied to another point in the circuit,
such as the base of that transistor. Varying the power supply
voltage then varies the dc bias on the stage, and the effects
may be noted. A series limiting resistor is often used to
protect the circuits from overdissipation.
ELECTRONICS MANUFACTURING
In electronics manufacturing facilities, the power supply is
often used as a dc power source while testing and adjusting
modules, subassemblies, and complete units in the production
and assembly area or in the quality control area. The
instrument can be used in incoming inspection as a dc power
source for testing purchased components and subassemblies.
This power supply is particularly well suited for
manufacturing applications because of its ease of operation
and its continuous duty rating. When load current or total
power dissipation are among the main characteristics to be
measured, the total load current and voltage are easily
displayed on the LED displays. The current limit can be set
so that all units which do not meet the load current
specification will cause the CC indicator to light, and the unit
can be rejected.
20