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Why would you use a relay to turn on something from a different power source?
One of the most common situations that require the use of a relay occurs when an application needs to switch from high to low current (or vice versa) within the same circuit. For example, the temperature sensors that power HVAC units require levels of amperage that vastly exceed the capacity of their wiring.
What type of relay is commonly used for switching operation?
Zero-Switching Relays
Zero-Switching Relays – relays turns ON the load when the control (minimum operating) voltage is applied and the voltage of the load is close to zero. Zero-Switching relays turn OFF the load when the control voltage is removed and the current in the load is close to zero. Zero-Switching relays are the most widely used.
How is a relay switch used in a circuit?
Switches are generally used to close or open the circuit manually .Relay is also a switch that connects or disconnects two circuits. But instead of manual operation a relay is applied with electrical signal, which in turn connects or disconnects another circuit.
What does the Dictionary say about a relay?
Dictionary says that relay means the act of passing something from one thing to another, the same meaning can be applied to this device because the signal received from one side of the device controls the switching operation on the other side.
Why are Relays usually in the off position?
Most relays are normally open; that is, the second, larger circuit is in the off position by default. In a normally open relay, power flows through an input circuit, activating an electromagnet. This generates a magnetic field that attracts a contact to join with the second, larger circuit, allowing current to flow through.
What kind of relay is used for make and break?
There are other contact configurations discussed below but make & break and changeover relays are the most commonly used.