On Dec 22, 8:26*pm, "MRe" wrote:
"sparky" schreef in ...
See this picture *HR)-60

http://www.universal-radio.com/CATAL...xvr/HRO60.html

it has a meter with the zero on the left.

On Dec 21, 7:39 pm, Kenneth Scharf wrote:





sparky wrote:
Why is the meter 'zeroed' against the right peg, is it
broken?
Or did National design it that way because they had a
backwards meter
circuit that pulled full current with zero signal?

This is a backward meter by National. The meter deflects left
when
current flows.

The radio must have had a backwards meter amplifier then.
Weird.
Guess one could design a proper solid state amplifier to make
it work,
but you'd have to 'zero' the meter at full scale with no
signal.

The AR88 had also a meter with the zero left (when there was a
meter anyway, because many had no meter at all)
It measured the cathode current of one of the IF tubes. (Less
amplification/cathode current means more signal). That leads to
the
somewhat odd 'zero right' configuration

MRe PE1NQr- Hide quoted text -

- Show quoted text -

Not sure one can understand the dilemma!
Lets say the meter is typically in the plate circuit of one or several
RF or IF amplifying tubes.
When the set is active and with no signal, the meter deflects (from
right to left). That type of meter is often called a 'Right zero'
meter).
When a signal is received a negative AVC voltage is generated; applied
to the grid circuits of the amplifying tubes their plate current is
reduced. The stronger the signal the greater the AVC voltage and ergo
the greater the reduction in plate current.
Hence the meter swings towards the right (or zero) in proportion to
the strength of the received signal.