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erod856 26th December 2012 10:59 PM

help with reading transistor
hey guys i always had interest in fixing car amp,i read alot of information on it so i have a little understanding of it,but wat been bugging me is getting a reading on resistor i think i know what they should read but i cant really understand wat the dmm is telling me i have a bunch of broken amp i collected over the years and every amp i get diff reading never the one im suppose to get. my understanding good resistor should read oL or one which mine says sorry for rambling on im just confused but really would luv to learn any help is very appreciated

erod856 26th December 2012 11:04 PM

sorry guys i meant transistor

ParadiseFreedom 26th December 2012 11:17 PM

The resistor reading will depend one it's location in the circuit.
A parallel resistor circuit will not give you the proper reading for an individual resistor.
Exactly what are you trying to do? Pics would help.

ParadiseFreedom 26th December 2012 11:19 PM

Well, in the case of the transistor you will want to locate a data sheet and look at the pinout.
You cannot measure a Fet type of transistor with a multimeter as you could blow it up or damage it someway with the multimeter.

Ian Finch 27th December 2012 08:20 AM

You need to read a technical book on electronics and/or repair. Picking up snippets of info on forums is no way to learn systematically about anything with technical content. If you want to successfully modify, repair and build audio gear, you need to learn a lot.

Here is one good start - there are other inexpensive ones too.,d.dGY

TANDBERGEREN 27th December 2012 10:10 AM

There is various ways a transistor failes, and the method of using a DMM in the resistor-measurement-mode reading OL as an indicator as if the transistor is OK or not is far too inaccurate to be used even as a fairly accurate reading.

Even when using the Diode-meassurement-mode there is several failures that can go "under the radar". Still more "safe" than the resistor-mode though.

There is a lot of quite inexpensive ways to get more accurate readings even on a DMM.
Many DMMs do already have a transistortester built in.
At least for small-signal transistors this one is quite accurate.
Also on the EBAY You find good transistortesters for as little as around $30,- wich can do a range of tests to the transistor in test, determing not only if it's good, but actually accurate enough to sort transistors to match them in a new design where matched transistors is preffered.
Good luck anyway.
The ladder You seems to have been started climbing is a fairly long one, and not all steps are as good as they seems to be. Just to warn You.

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