555 PWM Dimmer
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555 Data Sheet
This circuit varies the width of Astable Pulses.
It can be used to dim a lamp or control the speed of a motor.
This technique is much more energy efficient than using a resistor to control the speed or brightness.
Little waste heat is generated by this circuit. A resistor-based dimmer can get very hot, wasting energy.
Note the narrow pulses, the medium pulses and the wide pulses varying the power from about 10% to 50% and up to 90%.
Instead of using a potentiometer, this could be connected to a thermistor voltage divider.
An amplifier might be needed because the voltage changes from the thermistor are small.
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