I have a glass diode part number marking it shows

8.22. then goes back around to 8 again.

What is the part number for this diode it is in a DO-7?

thanks in advance

 

Could be an 822 in a DO-35 pkg 6.2V zener.

 

If it is a zener you can measure it with a 10mA current limited bench supply, or a bench supply and a series resistor.

 

If it is a zener you can measure it with a 10mA current limited bench supply, or a bench supply and a series resistor.

Experimenting with the DMM diode check function; I've found that zeners read much closer to the theoretical 0.7V than most other types of diode.

YMMV.

 

Experimenting with the DMM diode check function; I've found that zeners read much closer to the theoretical 0.7V than most other types of diode.

YMMV.

That is wrong polarity. And the DMM may not read beyond a volt to reach the usually higher zener voltages.

 

That is wrong polarity. And the DMM may not read beyond a volt to reach the usually higher zener voltages.

Its not the wrong polarity to measure the Vf - that voltage can tell you a fair bit about the type of diode.

 

Experimenting with the DMM diode check function; I've found that zeners read much closer to the theoretical 0.7V than most other types of diode.

YMMV.

How much closer?

I'm always measuring 4148 and 400x rectifier diodes on my fluke and they all measure close to 0.7v.

It doesn't sound like a very good test to me (although I will check it out in future).

 

How much closer?

I'm always measuring 4148 and 400x rectifier diodes on my fluke and they all measure close to 0.7v.

It doesn't sound like a very good test to me (although I will check it out in future).

Generally speaking; the lower the Vf, the faster the diode - there's actually a bit of a grey area between very small Shottky barrier (signal) diodes and the very fastest plain silicon.

Diodes like the 1N400x series come in around 0.65 ish - I don't have anything as fancy as a Fluke, but the results across about 5 different DMMs more or less agree.

 

Thanks, you have me intruiged now. I'll have to check it out.