Transistor or diode checking (was: Re: [ICOM] Need 2n3771's

[Paul Gates, KD3JF]

Thank you .... Appreciate that info. I plan to check the other transistors and resistors.

D C *Mac* Macdonald <k2gkk at hotmail.com> wrote: If it reads OL in "Diode Mode" it is
open and therefore very dead, Paul.

The resistors are likely open also
and probably show burned.


73 - Mac


----Original Message Follows----
From: "Paul Gates, KD3JF" 

Reply-To: ICOM Reflector 
To: ICOM Reflector 
Subject: Re: Transistor or diode checking (was: Re: [ICOM] Need 2n3771's
Date: Fri, 5 Jan 2007 07:20:16 -0800 (PST)

I have the diode mode on my DMM.

D C *Mac* Macdonald  wrote: OL signifies OVERLOAD, in 
other words infinite
resistance and therefore unreadable.  DMM's
are not too good for checking transistors unless
they have a "DIODE" mode.  This mode will
attempt to bias the diode into conduction and
should show approximately .65 volts for silicon
and .35 voltls for germanium junctions.  You
have to check each junction in both directions
of polarity.

If you are using a VOM you should show about
a 10:1 (minimum) ratio in resistance between
forward and reverse of a diode junction or
each junction in a transistor (BASE-COLLECTOR,
or BASE-EMITTER).

Mac - K2GKK/5
Oklahoma City, OK


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