How to control a bell,push button and a flashlight using a pin type relay

When electricity flows through the relay coil, it creates a magnetic field. This magnetic field pulls a metal contact inside the relay, causing the switch to change position. When power to the coil is removed, a spring returns the contact back to its normal position. Main parts of a relay Coil – produces magnetism when energized Contacts – open or close the circuit Common (COM) – moving contact Normally Open (NO) – open before coil is energized Normally Closed (NC) – closed before coil is energized How it works step by step Power is supplied to the relay coil. The coil becomes an electromagnet. The magnetic force pulls the contact arm. The contacts change state: NO contact closes NC contact opens The load device turns ON or OFF. When coil power stops, the contacts return to normal. Example A small switch can use a relay to control: Water pumps Motors Lights Air conditioners Industrial machines For example: A float switch sends a small signal to the relay. The relay then switches ON a large water pump safely. Common relay symbols COM → Common terminal NO → Normally Open NC → Normally Closed A1 & A2 → Coil terminals