How to use voltmeter？
Electromagnetic relays are a kind of common electrical appliances in industrial circuits. People who have a lot of choices for electromagnetic relays do not understand it. There are many questions about how to choose a good electromagnetic relay. So how do you choose an electromagnetic relay?
1. Select the rated operating current of the electromagnetic relay coil: For a DC electromagnetic relay driven by a transistor or an integrated circuit, the rated operating current of the coil (usually twice the pull-in current) should be within the output current range of the drive circuit.
2. Select the contact type and contact load of the electromagnetic relay: the same type of relay usually has a variety of contact methods to choose from (electromagnetic relays include: single group contact, double group contact, multiple group contact and normally open contact, often Closed contact, etc.), the contact type of the appropriate application circuit should be selected.
3. Select the power supply voltage of the electromagnetic relay coil: When selecting the electromagnetic relay, first select whether the power supply voltage of the relay coil is AC or DC. The rated operating voltage of a relay should generally be less than or equal to the operating voltage of its control circuit.
4. Choose the appropriate volume of the electromagnetic relay: The size of the relay volume is usually related to the size of the relay contact load. The selection of the relay of the approximate product should also be determined according to the request of the application circuit.
The relay is an automatic switching element with isolation function. It is widely used in remote control, telemetry, communication, automatic control, mechatronics, and power electronic equipment. It is one of the most important control elements.
Electromagnetic relay is an electronic control device. It has a control system (also called input loop) and a controlled system (also called output loop). It is usually used in automatic control circuits. It actually uses a smaller current. The lower voltage controls the larger current. An "automatic switch" for higher voltages. Therefore, it plays the role of automatic adjustment, safety protection and conversion circuit in the circuit.
The general principle of electromagnetic relay is to use electricity to generate magnetism and make the output end pull in or open. The static contact in the off state when there is no power is called "normally open contact"; the static contact in the on state is called "Normally closed contact".