[TechAssist] Re: Zener diode test
- From: Scott Beebe <Scott@xxxxxxxxxxxxxxxxxxxxx>
- To: Jim Myers <techassist@xxxxxxxxxxxxx>
- Date: Thu, 9 Jun 2005 14:51:20 -0400
Hello Jim,
I have built a Zener tester, that will go up to 200v and is good to test normal
diodes for reverse breakdown. I have a PDF of the instructions I used for
inspiration. The idea is there, but I went about it in my own way, with the
parts avail. I can send it out if anyone is interested.
Thanx,
Scott Beebe
Ohm Electronics Inc.
609 W. Clinton St.
Ithaca NY 14850
Voice: (607) 273-8406
Fax: (607) 273-8743
WWW.OhmElectronicsInc.com
mailto:Scott@xxxxxxxxxxxxxxxxxxxxx
Thursday, June 9, 2005, 2:15:38 PM, you wrote:
Jim> Look up MTZJ-T-77- in NTE and you'll find a fair selection of various
Jim> zeners, the first few on the list, up to 10 volts require a test current
Jim> of 20ma and the rest require only 9.5ma or less. Maybe a new battery in
Jim> your meter WOULD make a difference. In any case if they are used as a
Jim> protection device on the A/V inputs and are not shorted they are
Jim> probably not causing any problems.
Jim> ********************************
Jim> Since 1972 *
Jim> Jim Myers *
Jim> Telrad Electronics *
Jim> Fort Wayne Indiana *
Jim> ********************************
Jim> Paul wrote:
>> Yes, I agree. They appear to be just 1/2w Zeners, although
>> very small glass cases. I measured a 9.1v, 1w that I had in stock
>> and it measured fine on both meters. Interesting though, I checked
>> to see if they would zener and they do 9.4v. They still don't front
>> to back. How do you figure that? These are in a 2 year old set and
>> are used in the A/V input circuit apparently as protect.
>> Paul
>>
>> Jerome Silverman <greentron@xxxxxxx> wrote:
>> Sounds like plain vanilla 9.1 volt zeners. But to answer your question, some
>> "zeners" are actually ICs and some have one or more forward biased diodes in
>> series with the zener element and some may consist of two or more zener
>> elements in series.
>> Jerry Silverman
>> Greentron Inc
>> 4 Newland Ave Greenville SC 29609
>> Fax/Phone 864 232 3889
>> greentron@xxxxxxx
>>
>> ----- Original Message -----
>> From: "Paul"
>> To:
>> Sent: Wednesday, June 08, 2005 9:44 PM
>> Subject: [TechAssist] Zener diode test
>>
>>
>>
>>>Are there zener diodes that cannot be measured? I have 4 Sony zeners P/N
>>
>> MTZJ-T-77-9.1B on a board. They do not cross and I am guessing they are 9.1v
>> zeners. They all are either open or they do not measure. Have lifted one end
>> and measured with two different meters,Beckman and a Fluke still no reading.
>> Can't believe all 4 are open.
>>
>>>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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Jim>
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