Electromagnetic Relays Overview

Relays

• Relays are electromagnetic switches that use a small electrical current to control a larger one.
• The core component is an electromagnet, a coil of wire that becomes a temporary magnet when electricity flows through it.
• Relays act as an electric lever, switching on a larger appliance with a smaller current.
• They are crucial for controlling sensitive electronic equipment with small currents, enabling control of larger appliances with higher currents.
• Relays can function as both switches (turning things on/off) and amplifiers (converting small currents to larger ones).

Relay Operation

• Relays have two main parts: contacts and an electromagnet.
• Contacts function like mechanical switches, connecting or disconnecting electrical circuits.
• The electromagnet, powered by a different circuit, is responsible for triggering the contacts.
• When current flows through the electromagnet's coil, a magnetic force is created pulling a contact to another, creating a closed electrical circuit.
• When the current stops, the magnetism disappears, and the contact is restored to its original position.

Relay Necessity

• Small motors use minimal electricity, thus, small wiring and switches are sufficient.
• Large motors require larger currents and consequently, larger wires and switches.
• Relays overcome a crucial limitation: using smaller switches and thinner wires for large applications which are cumbersome and inefficient otherwise.
• Relays allow controls to be smaller and simpler and cabling between control boxes and motors more manageable

This quiz explores the principles and operation of electromagnetic relays, focusing on their role as switches and amplifiers. Understand how relays use a small electrical current to control larger appliances and the functionality of their key components, including contacts and electromagnets.