Re: Using a Panel Meter movement

On Mon, 15 Sep 2008 10:43:28 -0400, Patrick Keenan wrote:

> Hello All,
>
> I'm trying to sort out how to use an analog, needle-style, coild&spring type
> of panel meter movement. I have a couple of samples to play with,
> unfortunately I have no infomation about them. On one, the needle rests on
> the left, on the other, the in the center - this is actually the one I am
> most interested in using.
>
> For clairty this is the kind of device I'm referring to:
> http://www.process-controls.com/Modt...Taut_Band.html
>

The web site says they have "100 µA" movements - that's probably 0-100FS
for one, and 50-0-50 for the other.

So, take a 1.5V battery, a 10K pot, and a resistor of (1.5V/100 µA) ohms;

wire them like this:

+-----+
| |
- |
1.5V _ [10K]<----[15K]----+
| | |
| | [meter]
| | |
+-----+----------------+

That should give you zero to full-scale deflection. The 15K resistor
will turn a 100µA meter into a 0-1.5 voltmeter. Reverse the leads for
negtive deflection (like to test the 50-0-50 meter.)

Start the 10K pot at the low end (i.e., 0 volts) and crank it up
slowly, to make sure you have the polarity right and that I've guessed
right on the 15K value. ;-)

IOW, check my math! ;-)

Have Fun!
Rich