1. For example, if the output is a 50% square wave, the power consumed by the pulse width modulation (PWM) circuit is also 50%, with almost all power being converted to the load. If conventional resistancebased speed control is used to deliver 50% of the power supply's maximum output to the load, the power supply must provide more than 71% of the output power; 2.1. It primarily adjusts the duty cycle of the output rectangular wave to vary the average duty cycle of the load from 0100%, thereby achieving brightness/speed control of the load. The advantage of using pulse width modulation (PWM) for dimming/speed control is that the power supply can be fully utilized, resulting in circuit efficiency. 3. The full name of pulse width modulation is 'Pulse Width Modulator,' abbreviated as PWM. Due to its unique characteristics, it is often used for dimming in DC circuits or for speed control of DC motors. This circuit is designed for motor control based on the principle of pulse width modulation (PWM). Using this method for motor speed control offers the following advantages: 4. Of which, 21% is consumed by voltage drop and heat dissipation in the resistor. 2. Through the pulse width modulation (PWM) process, the load maintains the full supply voltage during operation, which helps overcome the internal coil resistance of the motor and allows the motor to generate greater torque.