MM0474
Figure 9.
RF Detection Bridge.
(3) Microwave power, applied to the thermistors, heats them further;
this decreases the error signal, reducing 10 kHz power just enough to balance
out the microwave power.
(4) The MOUNT RES switch, S1, changes the resistance arm of the RF
detection bridge so that the bridge will function with either a 100 ohm
unbalanced, 200 ohm unbalanced or 200 ohm balanced thermistor mount. The 200
ohm BAL position allows the power meter to be operated with balanced thermistor
mounts. When the MOUNT RES switch is in this position two equal capacitors are
connected in series across the thermistors with their common point grounded.
Identical capacitors are connected in a similar manner across A1R10 in the
resistance arm of the RF detection bridge. All other grounds are removed from
the bridge so that the
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