diodes - something new to me

[LightSoundGeometry]

got some diodes here , not sure what they are, but maybe 1n914 or 1n4148 ..something along those lines .. came from small bear or tayda for sure ..

some are testing out as double diodes??

 have never saw this on the tester even until now

lol

[antonis]

Zeners, perhaps..??

[Rob Strand]

What does the tester shows when you insert a zener around 3.9V or 4.3V?

What's weird to me is the tester thinks:
- the diode drop (767mV) is between 1 and 2.
- the zener drop is between 3 and 2
- but you have only got the part insert in terminals 1 and 3

In other words the measurements don't even match the physical connections.
It's like a hardware fault or software bug. 

The diode drop on 1 and 2 with the part in 1 and 3 seems the most puzzling because you would expect a diode drop measurement on 1 and 2.

What if you put the diode around the other way, or between terminals 2 and 3 (if the unit handles that).  If you have a good diode try it in a few different terminals an orientations to see what the tester shows.

[merlinb]

In other words the measurements don't even match the physical connections.

I think the display always shows 1 2 3, there's no connecting line to 2. Probably a 4.7V Zener diode.
It will probably have the number printed on it, look under a magnifying glass.

[Rob Strand]

I think it always shows 1 2 3, there's no connecting line to 2. Probably a 4.7V Zener diode.

Thanks, I just realized that myself.

It's looking more like a zener, where we do expect voltages in both directions.

The double diode graphic is general way of representing voltage drops in each direction.  If we know the part is a diode then a human would replace that symbol with a single zener but still show two voltage drop measurements.   We would only think a zener if one measurement was around 0.7V, If we got two 4.7V drops in each direction it would be something else (protection diode, series zeners).

[LightSoundGeometry]

thanks guys. probaly is a zener. I have only measured those on a dmm ..maybe i should put it on the dmm and test

there is writing on the diode, looks like a 23 or a 28

[merlinb]

there is writing on the diode, looks like a 23 or a 28

You could be reading 85 upside down, '85's are a series of zeners

[Rob Strand]

thanks guys. probaly is a zener. I have only measured those on a dmm ..maybe i should put it on the dmm and test

there is writing on the diode, looks like a 23 or a 28

The weird thing is a 1N5228 is a 3.9V 500mW zener.