Page "Radio-controlled car" Paragraph 10

Electrically powered models utilise mechanical or electronic speed control units to adjust the amount of power delivered to the electric motor.

The power delivered is proportional to the amount of throttle called for by the transmitter-the more you pull the trigger, the faster it goes.

The voltage is " pulsed " using transistors to produce varying output with smooth transitions and greater efficiency.

Electronic speed controllers use solid state components to regulate duty cycle, adjusting the power delivered to the electrical motor.

In addition, most electronic speed controllers can use the electric motor as a magnetic brake, offering better control of the model than is possible with a mechanical speed control.