I found a meter circuit on the below site that is almost
identical to the Bird unit. It will be easier to describe
the differences than to draw out the Bird circuit.
http://members.dandy.net/~k0xp/Technical/PEPMeter/PEPMeter.htm
In the Bird circuit:
R1 and R2 are 1500 ohms
R3 is 15k ohms
The second stage is identical to the first
R8 is 91k ohms
V1 is in series with the meter (25k) not a voltage divider
arrangement.
The Bird has a small LED indicator when it's in PEP mode
The Bird uses 9 volt batteries dropped to 6 volts by 6.2 volt
Zeners through 150 ohm resistors. Very wasteful!
I'm not sure of the value for the cap in the time constant
circuit. The markings are not revealing and I have not
unsoldered it to measure.
73, Roger
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