Electronics

PWM fan speed control methodology pulse-width modulates a fan’s full-rated power supply voltage at a low frequency, typically 30 Hz. A typical PWM circuit, consisting of a transistor in series with a fan, can be small and inexpensive because it is either fully on or completely off. This efficient control methodology affords a very wide speed-control range (typically 10% to 100% of full speed) because the fan motor is exposed to its full-rated voltage during the active portion of the PWM cycle.

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