Pulse Width Modulation (PWM)

Pulse Width Modulation (PWM)

Pulse Width Modulation (PWM) is a technique used to encode analog information in digital signals by varying the width of the pulse. It is widely used in electronic systems to control the power delivered to devices such as motors, LEDs, and audio speakers.

The basic concept of PWM involves producing a square wave signal with a fixed frequency and varying the duty cycle of the signal. The duty cycle refers to the percentage of time the signal remains high (on) compared to the total time of one complete cycle. By changing the duty cycle, the average power or voltage delivered to the load can be controlled.

In practice, PWM is achieved by using a digital signal, typically generated by a microcontroller or a dedicated PWM controller. The signal typically has a high state (often referred to as "on" or "1") and a low state ("off" or "0"). The duration of the high state corresponds to the "on" time, while the duration of the low state corresponds to the "off" time.

By varying the ratio of the on-time to the total cycle time, the effective voltage or power delivered to the load can be adjusted. For example, if the duty cycle is set to 50%, the signal will be high for half of the time and low for the other half, resulting in an average voltage or power level of 50% of the maximum.

PWM has several advantages in controlling devices. It allows for precise control over the power or voltage delivered to a load, enabling smooth and accurate adjustments. It is also an efficient method as it reduces power losses compared to other methods such as linear voltage regulation. Additionally, PWM signals can be easily generated and processed by digital circuits.

In applications like motor control, PWM is used to regulate the speed and torque of the motor. By adjusting the duty cycle, the effective voltage applied to the motor can be changed, thereby controlling its speed. Similarly, in LED lighting, PWM can be used to control the brightness of the LED by varying the duty cycle.

Overall, PWM is a versatile technique used in various fields, including robotics, power electronics, audio systems, and lighting, providing a means to control analog signals with digital systems.

• In this type, the amplitude is maintained constant but the width of each pulse is varied in accordance with instantaneous value of the analog signal.
• In PWM information is contained in width variation. This is similar to FM.
• In pulse width modulation (PWM), the width of each pulse is made directly proportional to the amplitude of the information signal. 

Pulse Width Modulation