In this video I telling about replays. A relay is an electromechanical device that consists of a coil and metal switch. Relays can have different connections, which called singe - throw, double throw and other connection. Relays also have diferent pole types. Relay also have voltage when they run.

In order to demonstrate how a relay works, we need build circuit. What do we need?

Jumper wires male-male

Jumper wires female-male

Power supply AC adapter for six volt one amper

Bottom

Relay five v one amper run

Breadboard

Two LEDs - different colors

Capacitor one thosand microfarad

Assemble the circuit like the picture.

You will see the on schem how it works. When you push the button, currents are flowed trow coil and capacitor, and then the coil switch relay. Current stops flowing through the coil, from batery. Capacitor is discharged and switch the relay.

Capacitor will be recharged again and again, and you see the relay start noise.

If you do not hane capirot one thousand microfarad, you can take less amonnt capitors and set those parallel.

EXPANDED TECHNICAL DETAILS

Power Electronics Foundation

A technical blueprint for safely and effectively interfacing high-current AC or DC loads with low-voltage Arduino microcontrollers.

• Flyback Diode Protection: Details the use of a 1N4007 diode across the relay coil to protect the Arduino from back-EMF voltage spikes during switching cycles.
• Coil-Driver Transistor Logic: Shows how to use a standard 2N2222 NPN transistor to provide the 70mA+ required by the relay coil, which exceeds the Arduino's 40mA per-pin limit.

Safety

• Galvanic Isolation Principles: Explains how the physical air-gap in an electromechanical relay provides total electrical isolation between the sensitive Arduino logic and the high-power load.