Section III. CIRCUIT ANALYSIS

C2, TM 11-6625-623-45

e. Input Jacks. I n p u t j a c k s J 1 - K C S T A B ,

isolating transformer T1 to the rectifier circuit

consisting of diode CR1 capacitor Cl, and in-

J3-KC STAB, J4-KC STAB, J2-IF TRANS,

and J2FREQ DIVIDER are used to bring test

ductor L1.

b. Rectifier Circuit. The rectifier circuit

signals from the receiver-transmitter to FUNC-

TION SELECTOR switch S1B.

t a k e s the 115-volt, 400-cps input power, and

rectifies and filters it to provide a direct cur-

f. FUNCTION SELECTOR Switch S1B.

r e n t (de) input to the calibrated dc regulator

F U N C T I O N SELECTOR Switch SIB connects

c i r c u i t consisting of Zener diodes CR3 and

t h e proper input jack to FUNCTION METER

CR4.

Ml.

c. Dc Regulator circuit. The filtered dc put-

FUNC-

FUNCTION METER M1.

put of the rectifier circuit is applied to the dc

regulator circuit which provides a constant lev-

TION

METER M1 gives indications of differ-

e l dc reference voltage to FUNCTION ME-

ences

between the reference voltage and the

TER Ml.

signal

being checked.

d. FUNCTION SELECTOR Switch S1A.

h. Dummy Microphone Circuit. T h e d u m -

FUNCTION SELECTOR Switch S1A con-

my microphone circuit is used to connect audio

n e c t s the proper reference voltage to FUNC-

tone inputs to the receiver-transmitter.

TION METER Ml.

Figure 1-1. Function test set, block diagram.

Section Ill. CIRCUIT ANALYSIS

power switch S3A, and 1/4-ampere fuse F1 to

1-6. Input Power Circuit

the primary of isolating transformer T1. One

(fig. 411)

pin of the secondary of transformer T1 is

The 115-volt, 400-cps voltage is applied

g r o u n d e d . The other pin provides alternating

t h r o u g h the power cable and connector J12,

c u r r e n t ( a c ) v o l t a g e t o t w o b r a n c h e s . One