A relay basically allows a relatively low voltage to easily control higher power circuits.
Arduino transistor relay control.
We have connected transistor base to arduino pin a0 through a 1k resistor.
In this quick arduino tutorial i will explain how you can control a relay using the arduino board one 1k and one 10k resistors 1 bc547 transistor one 6v or 12v relay one 1n4007 diode and a 12v fan.
1 x 1n4001 diode.
An ac bulb is used for demonstration.
The parts you will need.
When the button is pressed the fan will turn on and will remain in this state until the button is pressed again.
Circuit diagram and working.
The following circuit shows how to control a relay with your arduino or esp8266 microcontroller.
2 x 220ω resistors.
1 x tip120 darlington transistor is recommended but any one that will handle your relay will work.
The optocoupler is the most important part it isolates the circuit from the relay using.
The detail instruction code wiring diagram video tutorial line by line code explanation are provided to help you quickly get started with arduino.
Learn how to use relay with arduino how relay works how to connect relay to arduino how to code for relay how to program arduino step by step.
Arduino board jumper wires breadboard.
Schematic view of a potentiometer and transistor connected to an arduino.
The third leg is connected to ground.
You can use a 5v relay to switch the 120 240v current and use the arduino to control the relay.
The npn transistor is controlled by a digital i o pin of the arduino microcontroller.
In this example when a pushbutton connected to digital pin 2 is pressed the arduino will control a transistor via pulse width modulation pwm which will ramp up the motor s speed then slow it back down.
The basic transistor switching with arduino for arduino digital 7th pin is output if the arduino send logic 1 high the mini cooling fan turns on.
Below given is relay driver circuit to build your own relay module.
The arduino can only provide 40ma at 5v on its digital pins.
Therefore we use the 5v supply voltage for the coil and use a npn transistor to turn on and off the low power electrical circuit.
The picture above shows the circuit you need to build.
In this arduino relay control circuit we have used arduino to control the relay via a bc547 transistor.
The base of the transistor is connected to digital pin 9 of the arduino through a 1 kilohm resistor.
A relay accomplishes this by using the 5v outputted from an arduino pin to energize the electromagnet which in turn closes an internal physical switch to.
The second leg connected to analog in 0 of the arduino.
