The apparent brightness is caused by the ratio of on/off and is called the duty cycle. 50% brightness would mean that half the time the light is on, and half th

The apparent brightness is caused by the ratio of on/off and is called the duty cycle. 50% brightness would mean that half the time the light is on, and half the time the light is off. If the cycling of the light on and off is done at say 10kHz it's perceived as a dim light.