Re: Building DC Voltmeter


"vwq47" <vwq47@xxxxxxxxxxx> wrote in message news:cdlqi.12618$4A1.8307@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
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

You are already going in the right direction.
You have the range that you want but want to start at 8V. Cheap and dirty way is to insert an 8 V, zener in series with your resistance.
The meter won't start to read until 8V. and the readings will be 8V. less than actual. This is not real accurate and you will lose some linearity, but for automobile use you probably won't notice.

Tom

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