Analogue Voltmeter
Hi,
I'm looking for an ancient analogue voltmeter with the needle centered for zero position, to indicate positive and negative voltages.
Most desirable would be ±5V, but any range up to ±20V will do as well.
Does anybody know a source of those.
Thank you
Boncuk
Proper Planning Prevents Piss Poor Performance
Search eBay for "panel meter" and you will find items like this:
Centre Zero 1mA Moving Coil Panel Meter, Milliammeter - eBay (item 150370702849 end time Oct-04-09 11:14:18 PDT)
With a suitable series resistor, the full scale voltage can be whatever you like.
I tried 'Centre zero', it narrows it down.Originally Posted by The Electrician
I also tried 'Center zero' and got exactly the same results.
The problem is that there are some zero center meters in the "panel meter" category whose sellers haven't used the words "zero center" in the description, so a search won't find those.I tried 'Centre zero', it narrows it down.
I also tried 'Center zero' and got exactly the same results.
You will have to just look through all 1587 "panel meter" search hits to find those, and I know there are some in there; I've seen them.
Thanks for your replies, HouseOFwax and The Electrician,
I searched for "centered voltmeter" and the result was thousands of analog and digital voltmeters.
in the meanwhile the customer has decided to use two LED bars instead.
Boncuk
Proper Planning Prevents Piss Poor Performance
If is has to be a panel-mounted meter, you may be in for a tough search. If looking for an instrument that will do this, look to several: vacuum tube voltmeters could have their ZERO adjustment set to center value and most had a -|+ mark at center scale to set the pointer to; a transistorized voltmeter should do the same thing; a differential voltmeter not only can have a zero center indication, but you can offset that center by a precise number of volts and swing the pointer on either side of that.
For that matter, you can buy a nice differential voltmeter and ruin it by ripping the zero center meter out of it for your use. A pox on you if you take this advice.
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).
R.I.P.
If you get an ordinary 0-1mA movement, you can adjust the hair spring to create a centre-reading pointer.
Get a $10.00 multimeter from a Chinese $2.00 shop, or from an auto shop.
I've tried that already. No way to get the needle centered. (max. 1/3 of the scale)
Proper Planning Prevents Piss Poor Performance
I have done it may times and always got the pointer to centre-scale.
It just a matter of adjusting the hair-spring. You can desolder the end of the hair spring and reposition it on the pointer.
If you adjust to center and the meter was not designed for that will it still be linear? Will it be accurate on the low side or high side for that matter? My guess is some will some won't.
Will your application require the reading of overshoots? Will the meter still be usable for this?
Last edited by flat5; 20th September 2009 at 02:00 PM.
You are not affecting the linearity. You are only changing the sensitivity, in that a 1mA movement may now be a 1.1mA movement.
Thanks for the advise. I better forget about the analogue voltmeter, since the customer has decided to use two LED bar graphs instead.
Proper Planning Prevents Piss Poor Performance
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