BLOCK DIAGRAM DESCRIPTION

TM 11-6665-209-20

SECTION III

1-11. GENERAL

Radiac Set AN/PDR-27(#) is designed to detect beta radiation and measure and detect

gamma nuclear radiation. The AN/PDR-27(#) is used to monitor low level radiation

contamination on personnel and equipment. The highest reading (500mR/hr.) is ex-

tremely low compared with other readings likely to be encountered on the nuclear

battlefield.

1-12. BLOCK DIAGRAM DESCRIPTION

The AN/PDR-27(#) functions as shown on the accompanying block diagram.

RANGE SWITCH. Activates batteries and controls sensitivity of meter.

BA-30 BATTERIES. Supply operating power to the radiacmeter.

POWER SUPPLY CIRCUITS. Supply required voltages to the tubes in the probe and

to the amplifier and pulse shaping circuit.

REGULATOR CIRCUITS. Keep power supply circuit voltages constant so that

radiacmeter operates properly.

PROBE. Contains two Geiger-Mueller tubes which detect radiation. One tube is

associated with range switch position 500 to 50, the other with position 5 or 0.5.

AMPLIFIER AND PULSE SHAPER CIRCUITS. Takes pulses from the probe and com

verts them to constant amplitude pulses which are applied to the meter circuit.

METER. Indicates the amount of radiation detected by the probe on a scale.

HEADSET. Provides an audible indication of radiation detected by the probe.

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