Reference
Last revision 2026/01/06
This article explores the principles of relay operation, detailing how electromagnetic switches control circuit breaker switches, enabling low voltage inputs to manage high voltage circuits efficiently. A water level alarm schematic is also included to illustrate practical applications.
Principle
When the relay works, the electromagnetic switches off, which makes the circuit closed. When the electromagnet is powered off, the electromagnet loses magnetism, and the circuit is switched off. Therefore, the relay is used to control the operation of the circuit breaker switch.
The advantage of using relay control circuit is to control high voltage with low voltage input.
As shown below, this is a schematic diagram of the water level alarm. When the water level reaches the metal block A, the circuit will have a bright red light; otherwise, the circuit will have a green light.
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