Study of Pulse Width Modulation (PWM)

Experiment Name: Study of Pulse Width Modulation.

 Required Apparatus:

        I.            PWM Modulator

      II.            Oscilloscope

    III.            Power Supply

    IV.            Function Generator

      V.            DSS3 PWM Modulator (µA741)

    VI.            Connectors


Block Diagram:

Figure: Circuit Diagram of PWM by using µA741

Circuit Diagram:

Figure: Connections of Pulse Width Modulation


Input/Output Waveshape:


Figure 01: Waveshape of input signal

Figure 02: Waveshape of PWM signal while relevance voltage is 0V



Figure 03: Waveform of PWM signal while relevance voltage is +6V

Figure 04: Waveform of PWM signal while relevance voltage is -6V



From this experiment, we came to know about the concept of PWM and its practical basic implementation. We also observed the change in Pulse Width using different relevance voltage. When we apply 0V voltage the pulse width of positive and negative half cycles was equal. But when we apply +6V voltage, the positive half cycle was larger than the negative half cycle. Again, when we apply -6V voltage, then the negative half cycle was larger than the positive half cycle.



While doing the experiment, some precautions should be taken. Sometimes we can’t get the accurate wave shape because of the loose connection. And there was some distortion while calibrating the oscilloscope. So, we have to check the connection properly and we have to calibrate the oscilloscope accurately to get the accurate or proper wave shape.



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