helo m planning to use a TVS diode for voltage protection against the 10 V input.m using fuse and want to use zener diode for regulation...fuse rating is 2.5 A,50V ...so how can i do the rating of zener diode??what appropriate values shud i take?

 

A schematic would help.

 

To make any suggestions we would need to know:

1 what is the input signal and what the source resistance is
2 what are the limits of the input? How high & low can you drive it
3 is 10v a failure or normal part of the signal?

It may turn out that a fuse is overkill and just a resistor would do.

 

10 v is normal part...the range of input signal voltage that the device can handle is 10 V-40 V...
i havnt use any source resistance

 

The OP has asked almost the same question in at least two other threads
http://forum.allaboutcircuits.com/showthread.php?t=89341
http://forum.allaboutcircuits.com/showthread.php?t=89292
But still I have problems puzzling together what the OP really want to do.

 

The OP has asked almost the same question in at least two other threads
http://forum.allaboutcircuits.com/showthread.php?t=89341
http://forum.allaboutcircuits.com/showthread.php?t=89292
But still I have problems puzzling together what the OP really want to do.

I believe that is a problem you share with the OP.

 

The OP has asked almost the same question in at least two other threads
http://forum.allaboutcircuits.com/showthread.php?t=89341
http://forum.allaboutcircuits.com/showthread.php?t=89292
But still I have problems puzzling together what the OP really want to do.

ya i did ask 2 tyms,....but last 2 tyms also i havnt got any proper answer...if u know it my frnd,plz share it...rather than counting my posts...

 

ya i did ask 2 tyms,....but last 2 tyms also i havnt got any proper answer...if u know it my frnd,plz share it...rather than counting my posts...

You have got more than proper answers. Given the amount of details you have shared with us, and your effort put into it. Good questions draw good answers. As you may know none of us here in the forum. Are sitting next to you on your workbench. So we have no idea what you are trying to do. The key word here is proper specifications. We will be more than happy to help you. The moment you stop whimpering and put some effort into describing your problem capiche!

 

After reading the other posts mentioned, I kind of, figured out that you want a regulated output of 10V, from a supply of 10V - 40V, and the current is almost 0 (idle) and can go upto 2A when something is active.
Someone has already answered that you use a regulator rather than a zener diode. Linear regulator would be highly inefficient and need to dissipiate a lot of heat. A switching regulator would be better, typically LM2576 or LM2596 which can work upto 40V input. But you need to give atleast 13V as the minimum input.