Section III. PRINCIPLES OF OPERATION

TM 11-6665-209-40

TABLE 1-1

AN/PDR-27J

AN/PDR-27L

AN/PDR-27Q

COMPONENT

lM-141/PDR-27J

IM-173/PDR-27L

IM-195/PDR-27Q

4U1

CR101

1N485B

4U1

CR102

4U1

1N485B

4U1

CR103

4U1

1N485B

4U1

CR106

1N69

1N933

1N69

CR107

2T1

1N1626A

2T1

2N64

Q101

2N526

2N1305*

2N64

Q102

2N526

2N1305*

2N460

Q103

2N331

2N1305

2N64

Q104

2N526

2N1305

2N35

Q105

2N335

2N1304

R102

1K ohms

2.2K ohms

1K ohms

R111

680K ohms

100K ohms

680K ohms*

*Transistors Q101 and Q102 of AN/PDR-27Q, manufactured by Industrial Electronics

Hardware Corp., on Contract No. N0BSR87564, changed from 2N1305 to 2N526;

*resistor R111 same model was changed from 680K ohms to 100K ohms.

Section III. PRINCIPLES OF OPERATION

1-9. RADIAC SET BLOCK DIAGRAM ANALYSIS

Radiac Sets AN/PDR-27(*) are compact units when discussed consisting of nine func-

tional blocks which are described in Figure 1-2.

A Six 1 volt dry cells in series furnish all the power necessary for operation of

the equipment and, at 25C (77F), can power it for approximately 40 hours of continuous

operation.

B The power supply circuit converts the 9 volt DC power from the battery into

regulated +700 volts DC, which is fed to the G-M tubes in the detector circuit. The high-

voltage circuit uses a corona-discharge regulator tube V102 to keep the output voltage

constant.

1-3