Fuse and a diode in parallel to the most commonly used anti reverse circuit, the most commonly used anti reverse circuit is mainly the following:
Series 1 diodes

The circuit is simple and the cost is low, and the utility model is suitable for being used in the products with strict cost requirements.
The use of one-way circuit conduction diode, there will be insufficient pressure drop of about 0.7V, power must take this into consideration. This circuit is only suitable for use in small current circuit, if the access to a large current, then the power consumption on the diode will be increased, the heat can not be ignored.
Rectifier bridge

This circuit can be said to be an upgraded version of the circuit, a rectifier bridge, there is no power is then and reverse this argument, whether you‘re connected or reverse, followed by the circuit can work normally, as well as the principle of rectification.
The use of this anti reverse circuit, the cost will increase accordingly, the pressure drop will increase in 1.4V or so, only suitable for small current occasions.
Use a fuse and a reverse parallel diode

In the first two circuits, the voltage drop of the diode exists, which can only be used in the case where the load current is relatively small.
The anti reverse circuit is connected with a fuse in series, and a diode is connected in parallel. When the power supply is connected, as long as the load current does not exceed the allowable range of the fuse, the fuse will not be blown off, the diode reverse cut, no loss of input voltage, does not affect the normal operation of the load circuit. When the power supply is connected, the diode is turned on, the current is large and the fuse is fused, thus realizing the circuit protection function.
But the trouble is that every time we reverse the circuit, it is necessary to replace a fuse, it is inconvenient, you want to save effort can be recovered from the fuse.