When S1 and S4 are on, the left motor terminal is more positive than the right terminal, and the motor rotates in a certain direction. Here, the motor rotates in the direction dictated by the switches. The L298N motor controller follows the H-bridge configuration, which is handy when controlling the direction of rotation of a DC motor. This is where the L298N motor controller comes in. Obviously, you can’t drive loads that require much more current like a motor. There’s no problem there because the 20 mA or so current from the pins is enough. You can drive a LED on or off using a microcontroller like Arduino or PIC.
