fwiw

Howard Technician Alaska Posted   Latest   Edited  

Fwiw

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Interesting
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Joshua Technician
Texas
Joshua
 

Honestly, that is such a unique approach to testing diodes. I whole different route, once it was more frequent and bought a multimeter with a diode test mode setting to replace the one I had without it. 😭😭 I see a lot of people who use multimeter set on resistance, they don’t disconnect it from the circuit which give you some wild readings. I have used ohms, and checked both the diode in…

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Jeffrey Mobile Technician
Illinois
Jeffrey
 

I’m trying to figure out exactly why this is used. Diodes have generally 2.5 to 2.8 volt bias, meaning that the voltage needs to be above the stated voltage in order for current to flow. Simple button cell should do the trick. My impression of what your trying to describe is testing to see if there is a diode or resistor inside a relay? If you are then I don’t get how exactly this would work…

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Jordan Apprentice
Ontario
Jordan
 

Yes Im also wondering that. Examples please.

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Howard Technician
Alaska
Howard
   

See later reply

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Jeffrey Mobile Technician
Illinois
Jeffrey
   

My Fluke and BK meters I believe test at 3 volts and is enough to turn a LED on. I do understand your setup. Just one more question, why does is use less current in Forward bias than reverse bias, if I’m understanding correcty?

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Howard Technician
Alaska
Howard
   

Fwiw

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Randall Technician
Pennsylvania
Randall
 

Howard, Thank you for the post. I have always had a hobby of tinkering and making tools. I especially enjoy electrical devices. My latest is a relay tester. It’s at the shop, I’ll post a picture of it tomorrow. There is always something to learn or understand better. Randy

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Howard Technician
Alaska
Howard
   

Hi Randy Very interesting. I agree the vehicle batt is the route to take . Anyway, Consulab actually teaches this procedure using a test light and jumper . The atd 5500 circuit tester consumes 130ma so its safe for the diode and a jumper wire .

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Howard Technician
Alaska
Howard
 

Hi Randall Any updates on your tool?

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Randall Technician
Pennsylvania
Randall
 

Howard, Sorry it’s late, but I posted a few pictures of the tester. The one to the left, shows the entire set up. The 194 bulb confirms that it is connected to battery power. The LED confirms continuity through the relay coil. The upper halogen bulb is normally closed 87a contacts. The lower halogen bulb is normally open 87 contacts. The far right picture shows 87 contacts going closed and…

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Howard Technician
Alaska
Howard
 

Randall thanks for taking the time sharing your work. Not in anyway bashing ,my first thought was wow bright lights! I do note there are semi automated testers but yet still lack test functions as most aftermarket scan tools are. I too on my off time, find myself thinking as an age old question , Is there a better faster way around a problem while still being accurate? best advice given was…

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Randall Technician
Pennsylvania
Randall
 

Howard, I finished the tester back in January 2019. I wanted an easier way to do a dynamic load test on presumed faulty relays. I use it more for confirmation, than diagnostic. Relays usually cheap and readily available, I have kept most of the “bad” ones over the years and wanted to figure out if there is a better way. I have found that… The cycling of a relay with known bad contacts when…

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Howard Technician
Alaska
Howard
   

Randall that is interesting . cycling of relays , higher current from halogen load arc cleaning contacts by heat?

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