Pulse Width (PWM) Controller Circuit

A LM3900 quad operational amplifier can be used to build a pulse width (PWM) controller. The LM3900 was chosen because it only need single supply voltage of 4 to 30 V. This circuit can give 100 percent pulse-width control.  A1 op-amp forms a 1 kHz oscillator, generating a square wave oscillator for the basic oscillation. A2 is a ramp generator […]

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Pulse Position Modulator Using 555 IC

Pulse position modulation is similar to pulse width modulation, but the frequency is not constant.  Like pulse width modulator circuit, pulse position modulator can be easily constructed using 555 IC.  Here is the schematic diagram of the circuit: If you look at the output signal plot in the above timing chart, and compare it with our previous pulse width modulation, […]

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