Therefore we need a device to amplify the current.
Arduino relay transistor diode.
1 x sharp pc817 optocoupler.
Arduino board jumper wires breadboard.
Arduino tricks is the online education platform which teaches students every day that too completely free of cost.
Transistor acts as a switch to control the 12v to relay coil.
In this arduino relay control circuit we have used arduino to control the relay via a bc547 transistor.
The following picture depicts how to connect the different parts using a solderless breadboard jumper wires a transistor a diode a relay a push button and two 10k resistors.
B sc engineer in electrical and electronic engineering.
1 x 1n4001 diode.
Diode acts as a protection for transistor against back emf induced through relay coil during transit conditions.
An ac bulb is used for demonstration.
Therefore we need a device to amplify the current.
Below given is relay driver circuit to build your own relay module.
The picture above shows the circuit you need to build.
The base terminal of the 2n2222 transistor is connected to any of the digital i o pin of the arduino through a 1kω current limiting diode in this project base is connected to pin 7 of arduino.
Just a simple circuit that contains our transistor diode resistor and of course the relay.
Connections to the household appliance are not shown.
The following arduino program completes the post.
2 x 220ω resistors.
1 x tip120 darlington transistor is recommended but any one that will handle your relay will work.
The coil of the relay needs a large current around 150ma to drive the relay which an arduino cannot provide.
We have connected transistor base to arduino pin a0 through a 1k resistor.
The optocoupler is the most important part it isolates the circuit from the relay using.
The parts you will need.
Circuit diagram and working.
The project is used to demonstrate the high voltage driving capabilities of a relay using arduino uno.
The coil of the relay needs a large current around 150ma to drive the relay which an arduino cannot provide.
In this project the npn transistor 2n2222 drives the relay when the npn junction gets saturated.