Arduino Transistor Relay Circuit

Most motors require more current and or voltage to operate.

Arduino transistor relay circuit.

The picture above shows the circuit you need to build. 1 x sharp pc817 optocoupler. The arduino can only provide 40ma at 5v on its digital pins. In this arduino relay control circuit we have used arduino to control the relay via a bc547 transistor.

Usually an npn transistor in a common emitter configuration used as a switch drives the relay. Arduino board jumper wires breadboard. 1 x 1n4001 diode. The transistor in this example completes the motor s circuit to ground.

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. 1 x tip120 darlington transistor is recommended but any one that will handle your relay will work. 2 x 220ω resistors.

Below given is relay driver circuit to build your own relay module. Here is a simple circuit that uses a bipolar junction transistor bjt to drive a small 5 v relay coil. 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. The parts you will need.

The second leg connected to analog in 0 of the arduino. We have connected transistor base to arduino pin a0 through a 1k resistor. Schematic view of a potentiometer and transistor connected to an arduino. First leg of the potentiometer is connected to 5 volts.

The third leg is connected to ground. A transistor can act as a digital switch enabling the arduino to control loads with higher electrical requirements. 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. Circuit diagram and working.

A cheap general purpose transistor such as the bc548 is capable of controlling a small relay with a holding current of less than 300 ma. The optocoupler is the most important part it isolates the circuit from the relay using. 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. Thats it our circuit is complete now we can upload the code to the arduino to turn on or off the relay.