User manual

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and much more in the market. All these relay have same function but different in
specification [6].
Figure 3.21 : Relay schematic diagram
As known, relay consists of two separate and completely
independent circuits. One is at the bottom and drives the electromagnet. A switch is
controlling power to the electromagnet in this circuit. When the switch is turn on, the
electromagnet will produce flux, and it attracts the armature while armature is acting
as a switch in the second circuit. When the electromagnet is energized, the armature
completes the second circuit and the light will turn on. On the other hand, the spring
pulls the armature away when the electromagnet is not energized and the circuit is
opened. In that case, the lighting system will be in off mode [12].
A relay must be considered through several variables:
1. To activate the armature, user need to determined the voltage and current
2. Maximum voltage and current that can flow through armature and armature
contacts
3. The number of armatures
4. The number of contacts for the armature
5. Whether the contact is normally open (NO) or normally closed (NC)