Low voltage supply spike protection?

[60 oldjohn]

Originally Posted by Biggles

One point that may make this project a non-starter, or at least difficult to implement, is the fact that the electrical system of the vehicle would appear to be positive earth. The FM/AM converter board you are intending to fit will be almost guaranteed to be negative earth (unless it has been specifically designed for positive earth working). The zener regulator design would lend itself to either positive or negative earth working, but the module will be difficult to reference to earth without a lot of careful thought and insulating etc.
Alan.

Hi Alan, I am making the converter, so no problem re the positive earth. If I use a ready made module I might have a problem.
I intend using a SMD voltage regulator to reduce the 12-14volts to 3v. with the PCB mounted inside the radio case I may be able to make use of the inbuilt protection.


John.

[Biggles]

Ah, right. Just trying to maybe save you wasted time on a what may have turned out to be a bit more tricky than first thought. It's happened to me more than once.
Alan.