The PC25 is a printed circuit board which accepts the A225 charge sensitive preamplifier and shaping amplifier and the A206 voltage amplifier and discriminator. It is designed to be used for two purposes: to facilitate testing of these devices, together or separately, and to simplify their use in many applications. The board provides input test circuitry, gain adjustment, voltage reference for the A206, and convenient access to all active device pins. Ground plane construction minimizes noise pickup.
INPUT: A225, PIN 1; Charge preamplifier input. This input is diode protected and must be capacitively coupled to detector with capacitor of adequate rating. (Not supplied.)
DET: Input from detector. See Operating Notes.
HV: Detector bias voltage.
TEST IN: Input to test circuit as described in specifications.
TP OUT: A225, PIN 12; Timing pulse.
OUTPUT: A225; PIN 8; Shaped output.
VA OUT: A206; PIN 13; Voltage amplifier output.
DISC OUT: A206, PIN 9; Discriminator logic pulse out.
10, 11: A206, PINS 10 and 11, Monitor points.
Difference in potential between these pins is the discriminator threshold level set by "THRESHOLD ADJUST" potentiometer.
POWER and GROUND
JP1: A225, PIN 5; Output ground of A225. See Operating Notes.
VS: Power to the A225 and A206. See Operating Notes.
ADJUST (R3, R4): Potentiometer to provide trigger level for the A206 discriminator.
C1, C2, C3, C5: Filter capacitors.
CT: Test capacitor (2 pF).
RT: Test pulse termination resistor (50 ohm).
CW: Discriminator pulse width adjustment capacitor; A206, PINS 6 and 8.
RB: Resistor to bias A206 for bipolar inputs; 330 kohm from PIN 3 to ground. (Not installed.)
R5, R6: Gain control voltage divider.
CD: Differentiating capacitor for bipolar pulses. Direct connection for normal unipolar pulses.
U3: Voltage reference device.
HV Res: Detector bias resistor. (Not installed.)
HV Cap: Detector coupling capacitor (H.V.). (Not installed.)
SIZE 2.625 in x 1.750 in
(6.67 cm x 4.45 cm)