Can there be a zener diode without polarity sign?

Thread Starter

kandilar

Joined Mar 10, 2018
7
I got a "zener diode" which the vendor sold me as a 16V 2W zener diode.
It does not have a polarity sign and with a multimeter it seems always open!
But when I apply 25V or so (with a suitable resistor, of course) it reduces to appr. 17V.
It seems to be working!
How can this be?
 

WBahn

Joined Mar 31, 2012
27,913
I got a "zener diode" which the vendor sold me as a 16V 2W zener diode.
It does not have a polarity sign and with a multimeter it seems always open!
But when I apply 25V or so (with a suitable resistor, of course) it reduces to appr. 17V.
It seems to be working!
How can this be?
Does it do the same thing regardless of the polarity of the applied voltage?

If you put two zener diodes in series in opposite directions, then it will behave symmetrically like a zener diode that has a zener voltage of about one diode voltage drop higher than the actual voltage of the zener.

I've never heard of components being fabricated this way, but there's a lot of interesting components out there that I've never heard of.

Do you have a manufacturer and part number?
 

Thread Starter

kandilar

Joined Mar 10, 2018
7
It is an interesting device and I have never seen like it in my life with nearly 20 years of electronics experience.

I have connected it to a voltage of 28 V with a 12k resistor multimeter reads 17.58V.
When I have changed the "polarity" of this diode it reads 17.2 volts.
It more or less does its job it is supposed to.

Its brand seems to be ITT.
Does ITT produce such a component?
Here the pictures of the device
20181214_231329.jpg
20181214_231450.jpg
 

Thread Starter

kandilar

Joined Mar 10, 2018
7
I have never thought it would be a transil, missed it.
I agree.
Instead of zener the seller have sent me a transil, wrong shipment!
Thank you.
 
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