[TechAssist] Re: Diode testing
- From: Paul <dntwntv@xxxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Fri, 27 Aug 2004 10:31:41 -0700 (PDT)
Ed
I have a beckman and a fluke meter and they both test about the
same. The diode test setting is what led me astray. I always check for leakage
on the ohms scale after checking them on the diodes test.That is when I
discovered the odd things with these two. I had checked them in circuit before
mostly for shorts. When I pulled them out and checked them they both read lower
on the ohms sclae than what I consider acceptable. Heres the kicker. The new
diode just came in. On the 200ohms scale reads 11.6k one way and 26K the other.
Not all that different from the ones that I thought were leaking. Like I
mentioned usually they should show no reading one way. Hard to figure.
Paul
Edward Gaidies <teltek3@xxxxxxxxxxxx> wrote:
Paul;
Most digital meters have a diode testing position.
I use a Beckman 300. I don't know what the expected reading would be,
but after years of using the same meter, you get a feel for it.
Probably the same for ESR meters. May not always shoe what's on the
scale...but it's just a feeling.
-Ed-
Ed Gaidies
Tel-Tek Electronics
Ontario-Canada
teltek3@xxxxxxxxxxxx
On 26-Aug-04, at 10:10 PM, Paul wrote:
> When checking diodes for leakage, what range on the ohm meter do you
> use and is there an acceptable amount? Sounds like electronics 101
> but I have a couple of diodes that are flat case diodes mounted on a
> heat sink. They read 160 front to back on the diode check. No reading
> back to front. However they read 20k on the ohms scale. If heated this
> reading goes down to 2 or 3 K. I normally set my meter on 100k ohm for
> leakage. I thought they must be leaking. But wondered if there are
> some big diodes that test this way normally? Someone said that 10X the
> back to front was normal. These are in the secondary of a SMPS + & --
> 25v to convergence amps.
>
> Paul
>
> Paul ,B
> Central TV&Video
> 911W Grand Ave
> Grover Beach Ca.
> (805)481-8084
>
>
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Paul ,B
Central TV&Video
911W Grand Ave
Grover Beach Ca.
(805)481-8084
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