What's the use of fuse in power supply and the difference between Zener and Schottky?

[deepak.sibi]

1.A Simple 3 terminal Fixed regulator ckt is used to derive 5V from 12V supply.The schematics is fine its works for a few days but suddenly the vtg is not seen on the board.
What are the steps to debug the circuit,keeping in mind the Regulator IC is fine..


2.Why do we use Fuse in the Power supply circuit.Is it safe to use a 0 ohm jumper?How do
we differentiate the usage between them?

3.What is the diff btn a Zener diode and a Schottky diode.What are its applications...


Thks in advance
Deepak

 

[lladnar23]

Re: Doubts

The fuse is to protect the circuit in case of a short. You should replace it with a similarly rated fuse. Replacing it with a 0 ohm resistor will not necessarily provide the same protection (it might burn out and make an open circuit in the case of too much current, but then again, it might not!)
To troubleshoot, I'd just start out by process of elimination. Find a point in the circuit that does work, or has power, and trace through it. Also, double-check that your regulator is in fact good.

A schottky diode is a special diode where one contact is made from semiconductor and the other is made from a metal (typically). It works just like a normal diode, but with a lower forward voltage, somewhere around 0.2-0.3V.

A zener diode is a special diode that is designed to have a certain reverse breakdown voltage. I.e. if you apply voltage backwards, and ramp it up, no current flows up until a certain point, then the device breaks down and tons of current flows. They're good for building voltage regulators.