Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

How can I identify zener diode's breakdown voltage ?

Status
Not open for further replies.

pika

Junior Member level 3
Joined
Apr 20, 2002
Messages
27
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
Pocket
Activity points
108
Are there any circuits can measure zener diode's breakdown voltage?
 

mrcube_ns

Advanced Member level 1
Joined
Apr 10, 2002
Messages
452
Helped
48
Reputation
96
Reaction score
34
Trophy points
1,308
Location
Europe
Activity points
3,814
Its quite simple, you need power supply, resistor, and multimeter. Just conect diode and resistor in serie and both of them conect to voltage from supply. With multimeter measure voltage.

Regards!
 

barrybear

Full Member level 4
Joined
Nov 22, 2001
Messages
239
Helped
14
Reputation
28
Reaction score
4
Trophy points
1,298
Activity points
2,035
Obtain a 30/40 volt 100ma supply and feed it via a 10k resistor on to the kathode of the diode.place a meter accross the diode and measure the breakdown voltage/zener votage.
Barrybear
 

ptoo30

Member level 3
Joined
Apr 7, 2002
Messages
57
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
488
Hi pika
generally say zenner diode breakdown voltage is some distribution so when you measure the breakdown, youmay meaure the current via anode and cathode and it must be the same value as defined the spec (Iz) changing the series resistor value. Otherwise you cannot distingwish the fructuation on the mass line.
Additionally you may check the tempetature characteristics of breakdown voltage for wide temp range characteristic. Probably it is around -2mV/deg
rgz
 

Theexpert72

Newbie level 6
Joined
Mar 1, 2002
Messages
12
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
22
The temperature characteristics in reverse (normal diode) is around -2mV/K but in forward (zener) the tc is quite different! Values below say 5V have a negative tc and higher values have a positive tc! This however also depends on the biasing current, in old discrete power supplies this was used to generate a constant reference voltage over the temperature range.
 

tek547

Newbie level 4
Joined
Feb 24, 2002
Messages
7
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
90
To measure zener voltage, it's nice to have a current source. You can make a sloppy one with a lab supply (voltage source) and a pnp transistor. For example, connect the emitter of the pnp (2N3906) through a 600 ohm resistor to +vout of the lab supply. Connect 2 diodes (1N4148) in series between the +vout of the lab supply and the base of the pnp with the cathodes pointing towards the base. Connect a 47k ohm resitor from the base to the -vout of the lab supply. Finally the DUT (device under test), in this case the zener, connects between the collector of the pnp and the -vout of the lab supply with the cathode pointing toward the collector of the pnp. Now increase the lab supply voltage until the collector voltage (voltage across the zener stops rising). Read the zener voltage. The 600 ohm resistor can be adjusted for different currents. Good Luck
 

ptoo30

Member level 3
Joined
Apr 7, 2002
Messages
57
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
488
Hi Theexpert72
Yes you are right. The gamma-z takes from + to - temp coefficient. -2mv/deg is only lower zenner breakdown voltage rage. the tc depends on mamy conditions such as impurity,aneal,ion-implantation temp many. So itis not correct to say -2mV/deg as tc.
thank you
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top