The High Frequency Direct Current Relays are the electromagnet relays that work on the principle of attraction of electromagnet. These relays are suitable for various applications where reverse current, underload and overload protection is needed on the direct current circuits. They consist of a moving coil which is connected to the circuit with the help of a shunt. These relays can respond to a particular direction or magnitude of the flowing current through the shunt. The High Frequency Direct Current Relays acts as the automatic switches that control large voltage loads with the help of low voltage signals.