Out of a pile of diodes how do I identify a zener diode?

Thanks in advance.

Jack

 

Usually zener diodes write on them the zener voltage. The best way is to check the part number.

 

Mik3's suggestion is the very best way to do it, even though it can be a lot of work.

It's important to look at a datasheet for a Zener before putting it into use. They're tested for breakdown voltage at a specific current. If you attempt to use a Zener with it's current too far out of tolerance, you will be operating it in a non-linear region.

All that being said, see the attached (click on the thumbnail). An LM317 regulator is used as a constant current source, supplying roughly 20mA current. This should be low enough current to avoid "zapping" most Zeners. With the input voltage being 30v, the output of the LM317 will be at most 27v when the load is high resistance.

However, the input voltage is too high for many Schottky diodes, like the 1N5817 (20 PIV); they will be destroyed if their PIV is exceeded.

 

Another giveaway is the letter "B" on the end of the 1Nxxxx string.

 

Some have the "B" suffix, but not all; for example 1N4728A through 1N4752A.
Often, the suffix indicates tolerance; 'A'=10%, 'B'=5%, 'C'=2%, 'D'=1% (JEDEC format)
Other types use the suffix to indicate internal configuration; ie BAT54C = common cathode.

 

Hello,

Here is list of 1N - types of zener diodes.

http://tritium.fis.unb.br/Fis3Exp/fcim.csdc.com/fcimis/compid/semi/z_diode.html

Other lists of component numbers are there to.

http://tritium.fis.unb.br/Fis3Exp/fcim.csdc.com/fcimis/compid/semi/tashome.html

Greetings,
Bertus

 

Thanks for the information. Now I hope my eyes can read those small numbers.
Jack.....KD6MRF

 

There are small handy magnifiers which can help you to read these small numbers and letters.