Re: Building DC Voltmeter

On Fri, 27 Jul 2007 12:06:32 GMT, "vwq47" <vwq47@xxxxxxxxxxx> wrote:

I'm wanting to built a DC volmeter from a moving coil ammeter. I have all
the info and can calculate the series resitstor I need to make a (say) 1-20V
meter. It's an automotive use. What I would like to do do is offset the
zero so the zero reading is say 8V and the maximum 18V. I can't for the
life of me find a simple circuit that will work, though I knowq I have seen
them, using a regulator. Can anyone point me in the right direction please?

Thanks

dave


Try Googling "expanded scale voltmeter".

http://www.ibiblio.org/ecolandtech/alternative-energy/homepower-magazine/archives/2/02pg31a.gif for a
schematic and http://www.ibiblio.org/ecolandtech/alternative-energy/homepower-magazine/archives/2/02pg31.txt
for a text explanation of the circuit.

The 723 could be replaced by a TL431 shunt regulator or even a zener diode.

Mike


When truth is absent politics will fill the gap.
.