Driver is something that can control other electronic component, in this case something means electronics components or circuit. For example we need driver to spin motor, power up High Power LED, open or close solenoid, switch on/off AC lamp and many more.
Why use driver?
Driver is also a tool that needed to control other electronics component or circuit. Basicly why we need a tool to do something because it’s much easier when we use the tool or even we can’t do that thing without the tool. For example, why we need a driver to power a high power LED?
Let say we want to make blink LED with high power LED using arduino UNO. The LED has operational voltage 12V and current 500mA. How we do that? We already knew that arduino UNO has voltage output 5V and maximum current is only 40mA. If we force 5V and 40mA to power up the LED not only the LED that will not glow, but the arduino can damaged.
Drive a motor using transistor
Let’s take another example. Say we want to control a DC motor with arduino. The DC motor rating is 5V 1A. Now, we knew why we need driver. The motor need 1A current while arduino only can provide 40mA. If we connect the motor directly to ardunio, we can damage our arduino. And of course the motor will difficult to spin.
Now take a look at picture below
A motor connected to arduino directly, this means motor only has supply 5V and 40mA. Beside the motor will very difficult to spin, the arduino also can damage.
At the second picture, motor connected directly to batteries. The motor will spin fast, but we can’t control with arduino of course. 😛
So the solution taken from picture above. We can see that there is a resistor and a transistor used as a driver. The transistor is used to make motor draw current from batteries, not from arduino directly. So arduino still can control the motor, but the supply for motor is taken from the batteries. So the arduino will safe. Transistor here work like switch, and the arduino like our hand. The arduino will give signal to transistor through resistor and when transistor receive the signal, it will turn on the switch.