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