MM0474
(12) The meter is a 0-1 mA, full-scale meter chat has a capacitor across
its terminals.
The capacitor integrates the output pulses from the current
switch so the current into the meter is proportional to the time average of the
input pulses. That is, the input current to the meter is proportional to the
product of
(VCOMP + VRF) (VCOMP - VRF)
(VCOMP)2 - (VRF)2
=
(13) The output from the meter is further filtered so the voltage at the
rear panel RECORDER output is suitable for use with either a digital voltmeter
or X-Y recorder. The RECORDER output voltage is returned to the compensation
bridge through the automatic zero circuit when the FINE ZERO switch is
depressed. The automatic zero circuit holds a correction voltage at the input
of the compensation bridge amplifier, so when the RF is zero, the meter
indication will also be zero.
(14) The functional block diagram is further broken down in Figures 24,
25, and 26 with sheets 1 of 2 being the schematic and 2 of 2 a talking
schematic used for explanation of the circuitry.
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