The current regulators (next chapter) have an internal control that sets the constant current output, i. e. 350 mA. A second external control can be used for rapidly turning the current on and off. This is called strobing. The control inputs of the current regulators respond to a dc current of 5 mA into 1 kOhms.
The dimmer circuitry consists of an oscillator, running at about 1.3 kHz. Its triangular output is applied to one side of three comparators. The other side of the comparators receive a varying voltage coming from the motor-drive potentiometers (see previous chapter).
There are as many outputs per color channel as there are current regulators. Due to the different voltage requirements, the number of regulators varies from color to color.