Protection components of split type air conditioner electronic board

Fuse - intended to protect the circuit against excessive currents. They are constructed of special threads that break when a current flows higher than the one specified in their body; there are three basic types of fast, normal and delayed action fuse.

Varistor - is a resistor whose nominal value is a function of the voltage applied at the terminals are usually built in zinc oxide or chromium oxide.
Used for the elimination of voltage peaks introduced in power lines such as:
Key transfers in substations and atmospheric discharge (lightning).