The following three elements are critical when using relays correctly

(1) Relay rated operating voltage

The rated operating voltage of a relay is one of the most important technical parameters of a relay. When using a relay, you should first consider the operating voltage of the circuit in which it is located (i.e., the circuit in which the relay coil is located). The rated operating voltage of the relay should be equal to the operating voltage of the circuit in which it is located. Generally, the operating voltage of the circuit in which it is located is 0.86 of the rated operating voltage of the relay. In addition, some integrated circuits, such as NE555 circuit can directly drive the relay work, while some integrated circuits, for example, COMS circuit output current is small, you need to add a transistor amplifier circuit to drive the relay, which should consider the transistor output current should be greater than the rated operating current of the relay.

(2) Contact load

Contact load is the capacity of the contact. The contacts of a relay can withstand a certain voltage and current during conversion. Therefore, when using a relay, the voltage applied to the contacts and the current through the contacts should not exceed the contact load capacity of the relay. For example, the contact load of a relay is 28V(DC) x 10A, indicating that the relay contact can only work on a circuit with a DC voltage of 28V and a contact current of 10A, exceeding 28V or 10A will affect the normal use of the relay and even burn the contact.

(3) Relay coil power supply

This refers to whether the relay coil is using direct current (DC) or alternating current (AC). Usually, beginners in electronic production activities, are using electronic circuits, and electronic circuits often use DC power supply, so it must be the use of the coil is DC voltage relay.