Reed Relay
The symbol of a reed relay is:
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The following is a sample of a reed relay:
A reed relay is made of 2 iron stripes covered with coils of wire. The 2 iron stripes can be magnetized. When a current flows through the coils of wire, it generates a magnetic field around the wire. This magnetic field magnetizes the 2 iron stripes and thus the 2 stripes attract each other to close the circuit. When the circuit is complete, the components in the circuit will be turned on.
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When we draw the reed relay in a circuit diagram, the electromagnet (the coils of wire) and the iron stripes are drawn separately like this:
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When a current flows in the connection on the left, the coils of wire become an electromagnet and close the switch on the right circuit and turn on the motor. The advantage of this connection is that we can use a smaller current to turn on a circuit with larger current and thus safer.
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