SCR unit is a semiconductor device which acts as a switch formed by two thyristors in antiparallel. Each thyristor is like a one way valve able to go in conduction only when are satisfied these conditions: To form a real switch for alternating current is necessary to use two thyristor in antiparallel.

The speed of a fuse is essentially the time it takes for the fuse to open when a fault current occurs. The speed at which a fuse opens is governed by the material used in the fuse element, the overload current and the ambient operating temperature.

The primary use of an electric fuse is to protect electrical equipment from excessive current and to prevent short circuits or mismatched loads. Electrical fuses play the role of miniature circuit breakers. Apart from protecting equipment, they are also used as safety measures to prevent any safety hazards to humans.

Semiconductor protection fuses are used to protect against overcurrent conditions in power electronic equipment. They are specifically designed to reduce the I2t, peak let-through current and arc voltages during a fault condition.

Solar fuse is a type of protective device used in photovoltaic (PV) systems to prevent damage or fire caused by overcurrent or short circuits. It is an essential component of PV systems to ensure safe and reliable operation.