Using a Darlington Driver

Darlington Drivers are extremely useful components as they can turn a low power output from something like an Arduino into a higher power output which can be used to power components such as DC Motors etc.
It is quite a simple piece of kit to use but can give you some good results fairly quickly.
The ULN2803 Integrated Circuit (IC) I have used for these experiments is a simple IC to use and can be connected as shown in Fig 1.
For ULN2803 data please check:
https://static.rapidonline.com/pdf/82-0668e.pdf

The good thing about using an IC for this function is that you can connect more than one output if needed without requiring multiple transistors which can clutter your circuit board.
Just make sure you put the IC the right way round and connect the power rails as shown in Fig 1. A circuit diagram showing how Darlington Transistors are connected is shown in Fig 2.
You could have a go at connecting this circuit using Transistors if you wish to explore the theory side of this circuit further.

Once you have connected your circuit to an Arduino, test it using a program like the one in Fig 3.
Darlington Drivers can be used on the output of many circuits not just Arduino projects and as such are useful to practice with.
The example program below simply provides an output using a single section of the Darlington Driver. You will need to experiment to get the output you desire, depending on how you set up your circuit.

Fig 2

Fig 3

void setup() {  // initialize digital pin
pinMode(2, OUTPUT);
}
// the loop function runs over and over again forevervoid loop() {
  digitalWrite(2, HIGH); // turn the LED on (HIGH is the voltage level)
  delay(1000);   digitalWrite(2, LOW);
  delay(500); // wait  }

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