Arduino Transistor Relay Circuit

The arduino can only provide 40ma at 5v on its digital pins.

Arduino transistor relay circuit.

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. First leg of the potentiometer is connected to 5 volts. 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. I just programmed the arduino and attach with my homemade relay circuit board and connect all four appliances with the relay board.

The base of the transistor is connected to digital pin 9 of the arduino through a 1 kilohm resistor. We have connected transistor base to arduino pin a0 through a 1k resistor. The transistor in this example completes the motor s circuit to ground. Arduino board jumper wires breadboard.

The picture above shows the circuit you need to build. 1 x sharp pc817 optocoupler. Below given is relay driver circuit to build your own relay module. The second leg connected to analog in 0 of the arduino.

In this arduino relay control circuit we have used arduino to control the relay via a bc547 transistor. Here is a simple circuit that uses a bipolar junction transistor bjt to drive a small 5 v relay coil. 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. Most motors require more current and or voltage to operate.

Schematic view of a potentiometer and transistor connected to an arduino. 1 x tip120 darlington transistor is recommended but any one that will handle your relay will work. The parts you will need. The third leg is connected to ground.

The optocoupler is the most important part it isolates the circuit from the relay using. Thats it our circuit is complete now we can upload the code to the arduino to turn on or off the relay. 1 x 1n4001 diode. Circuit diagram and working.

2 x 220ω resistors. A transistor can act as a digital switch enabling the arduino to control loads with higher electrical requirements. An ac bulb is used for demonstration. Thats it our circuit is complete now we can upload the code to the arduino to turn on or off the relay.