[TechAssist] Re: Opto-Isolator testing
- From: "Dan Williams" <wizhd@xxxxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Tue, 26 Jul 2005 16:50:34 -0500
We do it close to that, except we use an analog meter to turn it on, and
digital to read ohms. This way there is no possibility of damaging
component.
Dan W
Wizard Electronics
Jacksonville, TX 75766
wizhd@xxxxxxxxxxxxxxxx
----- Original Message -----
From: "Christopher Barnak" <cbarnak@xxxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Tuesday, July 26, 2005 11:30 AM
Subject: [TechAssist] Opto-Isolator testing
> Yes Ken, I have tested many an Opto-Isolator by
> applying voltage to the secondary pens of the opto
> on the secondary side of SMPS. Either current limit
> your power supply or use a current limiting resistor
> or use the resistor that already may be there. I have
> had good luck without having to remove any componets.
>
> Connect your meter to the primary side of the opto and
> put it on diode or ohms. Start with 0v on the sec. side
> and gradually increase it (observe polarity). At some
> point the primary will go down to almost a dead short
> in ohms reading. The OPTO should be good if it does.
>
> The fixture thing sounds good, if the opto can easily
> be removed.
>
> But like you, lately I have been replacing it. I'm afraid
> of the possibility that the opto was damaged due to
> a overvoltage condition and may be intermittent or
> not work properly under operating voltages. I was
> bit by ONE of those boggers.
>
> Chris Barnak
> Norfolk Public Schools
> Norfolk, Va.
>
>
> -=-------------------------------------------------------------------------------------------------
> Jerry,
>
> That is a truly outstanding suggestion. I have often wondered how I
> could check an opto-isolator, but usually just replaced them if I had
> any
> doubts. Bet I've replaced lots needlessly.
>
> May try to build a test jig with a socket, battery, limiting resistor,
> and posts for a meter.
>
> You have helped many techs with that suggestion.
>
> Thank you,
>
>
> Ken Smith
> Gulf Technical Services
> 3034 Gulf Breeze Parkway
> Gulf Breeze, FL 32563
> 850-934-8324 (Voice) 850-932-0819 (Fax)
>
>
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