In-Depth: Control DC Motors with L293D Motor Driver IC & Arduino

Controlling DC motors with an Arduino requires an intermediate component because the microcontroller's digital pins cannot supply enough current to drive motors directly, and doing so risks damaging the board. This is where the L293D Motor Driver IC comes in. The L293D is a dual-H-bridge motor driver, meaning it contains internal circuitry that allows you to control the direction of two separate DC motors, such as standard TT motors. By sending high and low digital signals from the Arduino to the input pins of the L293D, you dictate the polarity of the voltage applied across the motor terminals, causing the motor to spin forward or backward. To control the speed of the motors, you can apply Pulse Width Modulation (PWM) signals from the Arduino's PWM-capable pins to the enable pins of the L293D, rapidly switching the power on and off to vary the effective voltage. The entire circuit is assembled on a breadboard, connecting the Arduino board, the L293D IC, and the DC motors together using jumper wires. An external 5V power supply is required to power the motors independently through the driver, ensuring that the heavy electrical load of the motors does not draw excessive current through the Arduino. Additionally, the L293D features built-in flyback diodes that protect the circuit by safely dissipating the voltage spikes, known as back EMF, that motors naturally generate when they stop or change direction.