Boonton 75D Instruction Manual page 23

Table 3. Controls and Indicator (Cont'd)
COMPONENT DESCRIPTION - FUNCTION
C ZERO COARSE and
FINE controls
(C302) and (C301)
CONDUCTANCE control
(R308)
DIVIDE G/MULTIPLY R switch
(S302)
R/G ZERO control
(R31 0)
TEST LEVEL control
(R305)
GAIN control
(R139)
PHASE control
(Cl 08)
Correlated variable capacitors. Used to
set up the Model 75D for operation by
balancing the capacitive portion of the
bridge network (with CAPACITANCE dial
set at zero).
Continuously variable resistor. Initially
set at zero when bridge is being balanced.
Dual-scale dial provides direct readings
of test specimen's parallel conductance and
equivalent parallel resistance. Conductance
(G) scale calibrated in umhos, and
resistance (R) scale calibrated in ohms.
Rotary switch with 4 resistive decade positions.
Extends the range of the CONDUCTANCE con¬
trol by using the switch factor to divide the CON¬
DUCTANCE G-scale reading and to multiply the
R-scale reading.
Variable resistor. Used to balance the
resistive portion of the bridge network (with
the CONDUCTANCE dial set at zero).
Variable resistor. Provides continuous
control of test-signal level from 1 mV
(fully counterclockwise) to 250 mV
(fully clockwise).
Variable resistor. Used to control gain
for both the phase detector and the
amplitude detector. Fully clockwise
position provides maximum gain.
Continuously variable capacitor. Provides
the proper phase relationship between
reference and test signals so that the phase
detector is insensitive to test specimen losses.
75 D
b-370
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