How to test one zener diode?

ScottWang

Joined Aug 23, 2012
6,898
The minimum current of Zener diode should be 5mA, so you can calculate the values of resistor.

You may choose 6~10mA to calculate the values of resistor, exp pwr=15V,
R = (15V-12V)/6mA=500 Ohm
R = (15V-12V)/10mA=300 Ohm
 

Thread Starter

disturbed987

Joined May 27, 2020
9
i apply voltage of 16,7 v from notebook supply. 16,7-12=4.7 volts divided on 1000 ohms is 4.7 mA.

i see 5.15 when zenner is connected with the black part to the power suppy
 

Thread Starter

disturbed987

Joined May 27, 2020
9
strange things are happening. I see 0.L in both directions without the zener beign in circuit.

I have put 3 new alcaline bateries in the measuring device which is Ms8217. The scale is AUTO and when connect the two probes i have 0.000
 

ericgibbs

Joined Jan 29, 2010
10,042
hi,
Inside your MS8217 when used to measure a resistance, the internal batteries apply a voltage across the component being measured.
If the component being measured is a semiconductor, the applied voltage on the test leads may forward bias or reverse bias the semiconductor, so the meter may give confusing resistance values.

BTW: Have you blown the internal Fuse of the MS8217 meter.???

E
 

Thread Starter

disturbed987

Joined May 27, 2020
9
i will measure its resistane with my mas830 C. is it an option ?

about the fuse i didnot remember. maybe yes but it should be replaced.i have my own service since maybe 7 years, but i do a lot with phones smartphones tablets and computers and i dont use the meter everyday.

i have other nickname here in forum but today i am on new notebook/my own has fault hdd/ and i dont have here my passwords.
I am the still not learned :D theunnameduser i think 159...
 

Thread Starter

disturbed987

Joined May 27, 2020
9
Please answer. Are you sure that when measure semiconductors with multimeter that have AUTO in resitance the measurment can be wrong ? If i think right i have tested MOSFETs with this dmm.

In thread i gave values in 2M scale and 200K scale - from the other dmm.
 

sparky 1

Joined Nov 3, 2018
184
Sometimes we use the meter as an approximation. When more precision is needed we can order a precision voltage reference and we know it is better than the meter. It can be annoying to put together circuit and see that your best meter has error. So with zeners when it works but is'nt perfect that's ok, just takes getting used to the accuracy of of the application.
One project I used 18 volt regulator then 15V then 12V with current control and filtering for noise. The skill set comes from doing like this thread.
 
Top