Resumo. The use of technology has become increasingly viable in classrooms, especially in physics classes. Explaining phenomena related to circuits becomes simpler when we can provide practical examples to students. The present article aims to describe the construction of a low-cost PWM module, which was used in the classroom to demonstrate the basic principles of digital electronics. The module was built with the 555 integrated circuit and a few other components. The assembly was made on a breadboard. The results from the operation of the board were analyzed with a digital oscilloscope and corresponded to what was expected in theory, the compatibility of the pulse width could be successfully verified, as well as the effect of simulating the analog output signal. Alternatively, the prototype was also used with an electric motor to visualize the influence of pulse width on the motor's rotation.