View Single Post
  #38   Report Post  
Posted to sci.electronics.repair
John-Del[_2_] John-Del[_2_] is offline
external usenet poster
 
Posts: 446
Default Resistance measurements

On Sunday, July 16, 2017 at 8:36:16 PM UTC-4, Phil Allison wrote:
Chris wrote:

--------------


I'm finding I get different results (vastly different in some cases) when
measuring the total resistance of a circuit with a) a DMM and b) an old
analog meter with a physical needle. And this doesn't only happen at high
impedance points, either. What could account for this?


** The fact you are totally clueless ?

Semiconductors are not resistors and there is no right value to measure.

DMMs are designed NOT to cause didoes or BJT junctions to conduct when using the ohms ranges.

Also, DMMs ohm ranges are very sensitive to any residual DC or AC voltage on a component while analogue meters are much less so.

Interesting fact: you can measure the resistance of a loudspeaker voice coil with either type, but not if the room is full of loud bass noise.

Think about it.


...... Phil


Come on Phil, lighten up. The guy didn't know and asked the question. We aren't all born full of knowledge; it's acquired by experience and asking questions.

Remember when you asked your mother why you have no friends, and she told you that you're obnoxious, pig headed and your feet smell like a fetid swamp? Same thing..