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What is PWM in microcontroller | Applications of PWM

This page describes PWM in microcontroller. PWM stands for Pulse Width Modulation. It mentions applications of PWM.

PWM stands for Pulse Width Modulation. It refers to variation in the pulse width. Now-a-days microcontrollers support PWM outputs. The digital pulses are available as output at these pins. The different pulse width will provide different DC voltages(average). Most of the microcontrollers will have built in timers which helps in generation of PWM signal with various widths. The low pass filters (usually RC type) are used to convert the PWM output to DC voltage. Following equation mentions relationship between average output voltage and duty cycle. The term duty cycle refers to ratio of amount of ON time and period of the pulse train. It is specified in percentage. Hence 10% refers to 10/100 and 90% refers to 90/100 in decimal format.


Average DC voltage output = Voltage to represent High State x Duty Cycle


PWM output
Fig:1 PWM signal with different DC outputs

The figure depicts two different PWM waveforms with duty cycle of 10% and 90%. This will generate different DC output voltages. This is used in brightness control applications in any technology. It is also used in speed control of motors.

Example:
For 3.28V and 10% duty cycle, Output = 0.328
For 3.28V and 90% duty cycle, output = 2.952

Applications of PWM | Pulse Width Modulation

Following are the applications of PWM:
• Brightness control in smart lighting systems by controlling voltage to LED driver connected with LED bulbs.
• Speed control of motors by varying voltage supply to it.
• It is also used as modulation scheme to encode message into pulsing signal for transmission.
Refer PWM vs PAM vs PPM>>.

Microcontroller Related Links

Refer our Page on microcontroller versus microprocessor which explains similarities and differences between both.
Refer our Page on microcontroller programming using C language including example.
Refer our Page on microcontroller development kit manufacturers.
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