Avoid smoke with power protection circuit

When designing an electronics device you want to make sure that it won't go in smoke under unexpected circumstances. You never know what may go wrong during life time of device especially if it is powered from mains. Jon Chandler made a great overview of common and pretty simple power protection circuits that may help to avoid lots of trouble. Small circuit between your battery and device may protect it from mistakes like reverse power polarity.

His lists starts with simple series diode which is cheap but may help protect from reverse polarity. Like any other it has a downside – voltage drop (0.7V) that may be a pain for low voltage devices.

The list continues with more smart solutions like Crowbar diode and fuse which avoids voltage drop but ends up with fuse blow on reverse voltage.

Using MOSFET is smarter way of protecting circuits. It gives a way smaller voltage drop – mV range with right MOSFET selected. This one is common way used in many circuits.

And of course, There are always specialized IC's that provide way better protection. Like LTC4365 protects circuit from reverse polarity but also from under and over voltage. So its your choice how much are you willing to pay attention to this part of circuit. And probably it is a “must” for expensive projects or end products where different things may happen.