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Author Topic: Cheap ammeter input impedance ?  (Read 857 times)

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Offline Back2VoltsTopic starter

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Cheap ammeter input impedance ?
« on: November 10, 2016, 03:52:44 pm »
This cheap ammeter gives a spec of   Input impedance: 5m?.    Are they talking about the sense current resistor?

http://www.ebay.com/itm/35-19-10mm-Mini-Ammeter-Meter-0-5A-Red-LED-0-36-3-Digital-Panel-BE-/201709674896?hash=item2ef6d56190:g:nS8AAOSwZVlXjyfE
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Offline Kleinstein

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Re: Cheap ammeter input impedance ?
« Reply #1 on: November 10, 2016, 04:21:47 pm »
The 5 mOhms is the shunt resistor. You have to add a little for the wires which is something like 17 mOhms per meter for 1.5mm² lines and a little for the board.
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