Hi,

I was wondering if anyone had any knowledge of polarity protection circuits? That is, a circuit that would protect a piece of equipment in the event that it were powered using the opposite polarity?

Tell you why I ask...

I use loads of guitar pedals in my recordings, and often run them from a couple of multivoltage psu's. These psu's have changable connectors and allow you to fit them at both polarities. The other day, I connected a pedal with the wrong polarity and was concerned that I might have damaged it. However, it all that happened was that the unit failied to operate. Once the correct polarity was supplied, it worked fine.

It was my understanding that supplying incorrect polarity would likely ruin a piece of equipment. But a friend suggested that the pieces of gear might have protection built into the design?

Knowing little about the design of these things, I wasnt sure if this were the case or not. Or more importantly, just how risky it is to accidentally connect to the wrong polarity?

What do you reckon lads?

Cheers,

TB

Difficult to say in general. Every box may have its own design.

On the ones I have built, I always added a diod in series with the power supply. A diod costs about 10 cents so that is not any problem. Sometimes with low feed voltages it could be a problam with the voltage drop of 0.7V (for silicon diodes).

Gunnar

Cheers gunner, appreciate the input.

From your own experience, would it be safe to say that IF a reversed polarity didnt fry a piece of equipment, that it would have such a protection?

TB