Arduino Transistor Relay Circuit

An ac bulb is used for demonstration.

Arduino transistor relay circuit.

A transistor can act as a digital switch enabling the arduino to control loads with higher electrical requirements. 1 x sharp pc817 optocoupler. So whenever i turn the arduino the first relay is on and its on for 3 seconds and after that it goes off and the second relay is on 3 sec similarly for third and fourth and after fourth all will be off for 3 seconds and after that all four legs will be turned on. Here is a simple circuit that uses a bipolar junction transistor bjt to drive a small 5 v relay coil.

This video npn transistor based 12v dc relay control drive simple make it this type transistor is a semiconductor device used to switch electronic signals a. The picture above shows the circuit you need to build. Basically when 5v flow through the 1k resistor to the base of transistor a current of about 0005 amps 500 microamps flows and turns on the transistor. 2 x 220ω resistors.

Basically when 5v flow through the 1k resistor to the base of transistor a current of about 0005 amps 500 microamps flows and turns on the transistor. 1 x tip120 darlington transistor is recommended but any one that will handle your relay will work. The parts you will need. First leg of the potentiometer is connected to 5 volts.

The second leg connected to analog in 0 of the arduino. The transistor in this example completes the motor s circuit to ground. Thats it our circuit is complete now we can upload the code to the arduino to turn on or off the relay. The optocoupler is the most important part it isolates the circuit from the relay using.

Circuit diagram and working. We have connected transistor base to arduino pin a0 through a 1k resistor. 1 x 1n4001 diode. I just programmed the arduino and attach with my homemade relay circuit board and connect all four appliances with the relay board.

Arduino board jumper wires breadboard. Most motors require more current and or voltage to operate. The third leg is connected to ground. In this arduino relay control circuit we have used arduino to control the relay via a bc547 transistor.

Thats it our circuit is complete now we can upload the code to the arduino to turn on or off the relay. Below given is relay driver circuit to build your own relay module. Schematic view of a potentiometer and transistor connected to an arduino. Usually an npn transistor in a common emitter configuration used as a switch drives the relay.