Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics 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.

zener diode usage for regulating of high voltages

Status
Not open for further replies.

sweethomela8

Member level 4
Joined
Apr 28, 2010
Messages
70
Helped
1
Reputation
2
Reaction score
0
Trophy points
1,286
Activity points
1,766
Hi,

I'm trying to use a zener diode (18.5V) reverse bias to ground with a source voltage that can range from 9 V to 30 V...I basically want the diode to conduct and regulate the voltage to 18.5 once the voltage gets that high. I'm using a 1 k resistor in series with the source, but get a very small voltage on the output (other side of resistor / zener diode), can anyone explain what may be going on? The current I'm drawing needs to support 2 amps atleast.
 

Well, your using a Zener to clamp a voltage. I suppose your clamping it using a back-to back zener diode. you should have a look at this **broken link removed**.
 

YOU MUST UNDERSTAND THAT ZENER DIODES requiere a minimum current to regulate correctly. And you can't expect that a 18.5 volts form the source the zener diode start the regulation.
For example for a 10Vz diode it is specified Iz = 25mA. You need a voltage greater than 10, in this example 15V.
R in series = (15-10) / 25mA =200 Ohms
So the resistor in series with the zener must be smaller or equal to 200 Ohms.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top