Tom Schlangen wrote:

Hi Jan,

all I can say is WOW ... because it even saw
real world implementation =:-)
But the principle is clear.

Tnx2u!

I have a logarithmic amplifier using a 741 opamp,
and a shunt fb path using a diode, and a resistor,
and this powers a meter which has a center zero point.
The log amp allows me to read +/- 40 dB easily in Db, rather than volts.

I use the meter for sound level readings from speakers, which vary
a lot, and to cope with variations, I need a log meter.
But such a simple arrangement could be used to
alter the grid volatge of a magic eye tube.

Patrick Turner.


Tom

--
Knowledge is power - knowledge shared is power lost.
-- A. Crowley