PWM means pulse width modulation, in simple words it means to modulate or change the width of a generated pulse. The circuit which is engaged in doing this particular activity is called a PWM signal generator circuit.
The pulse generated by a particular circuit are in fact ordinary square waves or in simple words alternate generation of high and low signals or alternate generation of positive and zero volts. The rate at which these are emitted is called th frequency of the pulse.
Electronic Circuit FAQs? ASK ANY CIRCUIT RELATED QUESTIONPWM control may be achieved either by changing the distance between the pulses or by changing the width of the pulses through some external means (circuit).
If these pulses are spaced very close to each other then the average value ofthese pulses will be very close to the supply voltage and as the space between these pulses are increased the average value also decreases proportionately.
It simply means that by dimensioning the pulses, the average value of the output can be adjusted precisely and used to control an output device such as charging a battery etc.
A very simple circuit of the above discussed PWM generator circuit using the versatile IC 4060 is discussed here. The circuit employs optimizing the width spacing of the generated pulses rather than the width itself.