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Testing Transistors With Digital and Analogue Multimeters.

HellasTechn

Apr 14, 2013
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Hello !

I have a silly question of which the answer i am sure is simple. Why when testing transistors with DMM we put positive probe to P side and negative to N side while with AMM we go reverse (negative to P side and positive to N side) ?

Thank you !
 

BobK

Jan 5, 2010
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What settings are you using on the multimeters? If using a diode check setting, it should be + to P - to N, but if using a resistance setting, the opposite.

Bob
 

duke37

Jan 9, 2011
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Because of the circuit in the analog meter, The red lead is negative. Doubtless this simplifies the switching.
 

HellasTechn

Apr 14, 2013
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I use the diode mode for the DMM and resistor mode (usually mid scale like x10 or x100) for AMM
 

dorke

Jun 20, 2015
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Like @duke37 said it is because the older Analog meters have the internal battery positive feeding the (-)black lead.
Newer Analog Meters(and AVOs) and Digital ones have it connected the conventional way positive to (+)RED.
So for analog meters you never know before you actually test the polarity or look at the schematics of the meter.

AMM.jpg
 

HellasTechn

Apr 14, 2013
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That makes sense.
Thanks for the info :)

Have you noticed that With an analogue Multimeter you can more reliably test components like transistor's specially darlington and Fet's ?
 
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