How to Test A Zener Diode

How to Test A Zener Diode presented by Galco TV. Buy the items featured in this video at 800-337-1720 or visit:www.galco.com/s...
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[@charlesbrasil2837]

This is the best video about this subject that I have ever seen. Thank you !

[@kabandajamir9844]

The world's best teacher

[@vader7725]

how do you know which type of zener diode to search for data? Is it by reading the number on the diode body?

[@j5892000]

yeah its all well and good when its your own diode and not one you randomly pulled from a circute

[@johnruscigno5738]

Where did you find that zener diode? I've never seen black one's before. They looked more robust than the tiny red one's.

[@pankajB66]

That's not a zener diode.

[@doublesnake18]

Simply that's not a zener diode ...

[@johnruscigno5738]

Nte 139a was the number he said and I looked it up, it's a zener diode

[@johnruscigno5738]

Google it guys, it's a black zener, trust me.

[@doublesnake18]

@@johnruscigno5738 Yep, i found it ( btw, first i found an helicopter lol )

[@donaldfilbert4832]

Would this also work testing the reverse breakdown of a Schottky diode? When I tried it - I got no current - even for 10 volts over the Schottky breakdown voltage (Schottky Vr = 20 V. tested reverse voltage = 30 VDC). The full voltage drop read across the Schottky (30 VDC) - and NO voltage read across the resistor (which was only 10 ohms). Am I missing something ??

[@74LS324]

I have a switching power supply. The voltage swing is around 1 Hz. Zener replacement solved this problem. But the faulty zener passed the multimeter test and the voltage limiting on the dc load. So how to test zener for high speed operation?

[@danfuerthgillis4483]

We'll checked the voltage on the zener and getting 3.2 volts using a 1K ohm resistor and a 9v battery. It's a 751 Zener as marked on it so I believe it needs to be replaced. almost done fixing the Memory Man deluxe!!

[@GalcoIndustrial]

Sounds like you are on the right track.

[@mrcesporinas1041]

bro my indcution heater metal melter is 3500watts and input v is 48v what is the correct zener diode need to use it?

[@AJ-pg8qe]

isa kanang activity sa elecs, mabuhay ka

[@naderhumood1199]

Good apprauch. Sir.

[@DhakaMusicOmar]

where was the information?

[@stevetobias4890]

OL means "Outside Limits" not "Over Load". Great video however, great information.

[@jimc52]

Maybe I am mistaken, but isn't that diode's cathode pointing to the positive terminal of the battery? I thought diodes are forward biased in order to read voltage. That would means the diode has to be reversed in the diagram.

[@johnc3375]

Yes James that is correct for standard rectifier diodes. Zeners regulate in the reverse bias direction though. In our video you see us test the Zener's forward bias voltage at 0.627 volts, this is because zeners are diodes too. However they must be put in reverse bias direction to get them to break into regulation mode. Hope this helps.John

[@Synthematix]

OL means open loop, not overload

[@meherhjb7170]

I think OL means open line Thank you

[@brutusjb3814]

WHat if you get continuity across the diode to +/-

[@Sidicas]

You need to use diode mode on the multimeter. Usually it is the same position as continuity and then hit mode select to switch to diode mode. -|> Continuity does not test direction but diode mode does and direction of flow is how you test a diode.

[@SteverRob]

Iirc "OL" means "open loop"

[@gjidy7715]

How to check t2d dioes?

[@rkmag1141]

I though OL means Open Line

[@gordthor5351]

What about the orange glass zener diodes? I have one shorted in an expensive preamp that never had a schematic. Is there any method of determining it's value to replace it?

[@paulf1071]

Just wondering if you ever figured out the Zener voltage of that orange glass type diode? (If badly stuck, I suppose you could try a high value, and work downwards until the circuit works as expected ??)

[@Formula400Pontiac]

I has always thought that OL mean Over Limit.

[@kylethompson3187]

Open Loop

[@martinkuliza]

it does mean OVER LIMIT idiots who don't know how to use their brain say OVER LOAD

[@martinkuliza]

@@kylethompson3187 it doesn't stand for Open Loop, it stands for Over Limit Meaning that the meter has a Limited measuring range and anything above it is represented by OL. Open Loop is something that someone back in the 70s dreamed up based on the fact that When you measured continuity and you have an OPEN CIRCUIT aka OPEN LOOP it would say OL, that's where that comes from Not everything is an open loop EXAMPLE : if the limitation of your DMM on Resistance is let's say 10 M Ohm and you want to measure a 15M Ohm resistor - The resistor is good - Your meter is good - There is no Open Circuit between the test points - HOWEVER YOUR METER WILL READ OL or , depending on the meter it might read 1 which is a substitute for OL the reason this happens is YOU HAVE EXCEEDED THE LIMIT OF THE MULTIMETER another way of saying Open Circuit is INFINITE RESISTANCE, or INFINITY as some like to loosely call it so.. the lesson for today is IT'S CORRECTLY CALLED OVER LIMIT

[@AHMAD0SHISHANI]

Over load

[@martinkuliza]

@@AHMAD0SHISHANI it's not over load jesus, Use some common sense WHY THE FUCK WOULD IT MEAN OVERLOAD if you're testing a wire in continuity mode and you cut the wire (hence it's open Circuit) WHERE IS THE OVERLOAD ? No mate 2 Terms are accetable Open Loop (but this doesn't work in some measurements) or OVER LIMIT which means In continuity mode - There is high resistance and.. THE METER CAN'T DISPLAY THE EXACT AMOUNT, hence it has gone OVER THE LIMIT OF THE METRES ABILITY TO MEASURE THE RESISTANCE you can also call this OPEN LOOP if you like (but it's not correct , but does work in this scenario) in Voltage Mode - You can't use Open Loop it's OVER LIMIT because if you have a meter that will test up to 600V and you try and test 620V you will see OVER LIMIT (OL) simple as that in Resistance Mode - Same thing, you go over the limit of the metre's ability to display the number and it shows OL it's over limit it's not Overload how the fuck can it be Overload ? DID YOU EVER STOP TO THINK ABOUT THIS ?

[@AP9t9]

Why resister is used to measure zener diode...

[@GalcoIndustrial]

Because it gives the remaining voltage somewhere to go. Notice they use a 12 volt supply across the diode and resistor, ok? So the 12 minus 9.1 = 2.9 right. This keeps the current thru the diode from going way beyond its range of operation once it breaks into zener mode.

[@danfuerthgillis4483]

Great Simple video. I have a Zener Diode here that measures 1.82 v on the reverse diode test I believe this diode is shot anyone can anyone help? as I think I may have to order some...

[@GalcoIndustrial]

That is probably a safe bet. Zener diodes basically measure the same as a rectifier type will, except maybe a little higher forward bias voltage like 0.7volt instead of 0.6. Reverse biased they will measure open like a rectifier until you reach the Zener voltage value. Do you know what it is rated?

[@danfuerthgillis4483]

GalcoTV Thanks for the reply will test the rated voltage with the 1k ohm resistor and 9 v battery but since it is giving me a 1.8v when doing the reverse diode test when it should be OL there is really no point in going further so I ordered the 751 zener . I have the schematic for the Memory Man Deluxe and I already replaced the dead Voltage regulator (it is a -15v), however checking more the Zener also was probably dead as well.

[@GalcoIndustrial]

Very good Danfuerth, my research shows that a 1N751 is supposed to be a 5.1 volt Zener anyway.

[@danfuerthgillis4483]

GalcoTV​ Hey I really appreciate your responses and your info. Checked all resistors on the PCB and rectifier diodes those all were okay. The Memory Man Deluxe (Ec2000 PCB) uses an unusual -15 v negative voltage supply which is regulated by the newly installed and working Voltage regulator( from 34v DC supply) . However without the critical Zener voltage flowing the Voltage will not flow to the LED's which in turn pass voltage to the main system. Thanks again!!

[@Impulse_Photography]

@@GalcoIndustrial I thought, the zener diode is supposed to conduct current in both directions - unlike a regular diode, and they have a different voltage in each direction - you should really search-out the data sheet for that diode and see what the Ef and the Er are for that diode.

[@Technicaldmk]

Sir it's not a zener it's a 4005 simple diode😊

[@thecuriousone9342]

the first was a diode not a zener

[@GalcoIndustrial]

it's a zener diode.

[@JoseRamirez-zb3ix]

no its not

[@GalcoIndustrial]

Yes they were all zener diodes. The first diode visible is a 1N3339 which is a 91 volt zener and the same tested with the multi-meter. The NTE diode tested in circuit was also a zener.

[@swedensy]

It iz zener. Part number shows. Just like transistors can look like diodes and IC.

[@simonspeaker]

its a zener diode

[@echothehusky]

Very helpful, thank you. Also I'm like #666!

[@hassanniaz7583]

Well nobody gives a shit

[@bencheyne1333]

OL means open loop.

[@durgeshgupta-do9iq]

Good. Suggest

[@Atetus94]

OL means Open Line

[@CurvedSlightly]

*over limit.

[@sarfrazz34]

hey that's diode man

[@FixDaily]

It can also be a zener, they can be alike silicone diodes.

[@idoesstuff]

guys that is not a zener diode

[@AviJoncic]

This is schottky diode bro, not zener!!!!

[@GalcoIndustrial]

No, it's a Zener Diode. The first diode visible is a 1N3339 which is a 91 volt zener and the same tested with the multi-meter. The NTE diode tested in circuit was also a zener.

[@FixDaily]

If that was a 9.1V zener diode you would never be able to read it with your multimeter because your multimeter doesn't have enough voltage to read the drop across it

[@swedensy]

FixDaily - Electronic repairs, hacks and tips my god. He used test circuit for that reason

[@EricP36]

First!

[@PhuckHue2]

Not a Zener dummy