Chapter 5. CIRCUIT FUNCTIONING

TM 11-6625-539-15-2

CIRCUIT FUNCTIONING

5-1. Introduction

Circuits for Test Set, Transistor TS-1836B/U can be

divided into four functional loops: Multivibrator,

current limiting, audio amplifier, and switching. The

multivibrator stage produces an amplified square

wave signal that is applied to the switching circuits

through coupling transformer T1. The current limit-

ing network is provided for the protection of the

semiconductor under test and to limit the current to

the transistor when resistance tests are conducted.

The audio amplifier is used in conjunction with the

F.E.T. test to provide a parallel source to operate the

meter. The switching circuit incorporates a 12-posi-

tion, 9-wafer function and a 3-position, 12-pole 3-

wafer type polarity (FND PNP/OFF/REV NPN)

switch.

5-2. Battery Check

A simplified schematic diagram of the circuit used to

Figure 5-1. Battery check, simplified schematic diagram.

check the batteries in the test set is shown in figure

5-3. Beta and Diode In-Circuit Checks

5-1. With the function switch in the BAT. position,

+9 volts is fed through series resistor R32 and meter

a. A simplified schematic diagram of the circuit

M1. The resistance of R32 limits the deflection of

used to calibrate for beta is shown in figure 5-2. Fig-

ure 5-2 illustrates a PNP-type transistor; however,

meter M1 to the BAT position on the scale.

Figure 5-2. Beta and diode check, simplified schematic diagram.