Hi, I have recently built a dc-dc converter to convert supply voltage from 6V to 32V, the circuit diagram is as below:


and the circuit on the breadboard is looks like this:


My friend has built one with the same circuit diagram, I have double checked with him, both circuit connects exactly the same with same components, he circuit is working perfectly fine, but my circuit has a problem. my output voltage jump to the 42V, slowly drops to 32V, jump up again to 42V, slowly drops and it repeats this process over and over again. I have no idea what is wrong with it.

Here is how my friend circuit looks like:


Any help will be appreciate!

Thank you!

 

One thing that might help is to move your circuit to a circuit board and solder the connections. Those plastic breadboards are not designed to handle much current and the connections can become intermittent with time, especially when using components like capacitors with large diameter leads.

 

One thing that might help is to move your circuit to a circuit board and solder the connections. Those plastic breadboards are not designed to handle much current and the connections can become intermittent with time, especially when using components like capacitors with large diameter leads.

I wouldn't use one of those boards at any point in the development of an SMPSU.

My preference is the "dead-bug" method of prototyping. Usually I start with a 16SWG frame carrying the input power rails and held together with the filter capacitors. The leads on the components furnish most of the wiring,18 or 20SWG wire can be used to fill in where needed.

Stretching a length of tinned copper wire leaves it completely straight, so you can form it into the required shapes with a neat and tidy end result.

Once a circuit is just right, you can pot it instead of starting over on a PCB.

 

It is the problem with breadboard. Problem solved! thank you!