What is RC ESC? What is BEC/UBEC? What does BEC/UBEC do?

ESC (Electronic Speed Control) is a speed control circuit used to control the speed of electric motors. It is used in remote control model vehicles with electric motor. So it is part of the hardware for model airplanes, cars, boats, helicopters and drones. Without ESC we cannot control the speed of the motor. And the motors cannot be connected directly to the receiver.

Brushless ESC is required for brushed motors, brushless ESC is required for brushless motors.

Motor, Battery and Receiver Connection with RC ESC:


What is BEC/UBEC as a feature of ESCs? What does it do?

ESCs usually feature BEC or UBEC. BEC (Battery Eliminator Circut) and UBEC (Universal Battery Eliminator Circut); The task of these two features is the same. These are voltage step-down circuits. But the working principles are different. BEC circuits are linear voltage reducers. They cost less, but their efficiency is somewhat lower. UBEC circuits are switched (Switchmode) voltage reducers. UBEC circuits are more efficient, generate less heat, but cost more. Whether an ESC has BEC or UBEC is not related to its ability to control engine speed. And it does not determine the quality of the ESC. Because the motor speed control feature is independent of the BEC/UBEC function.

As a result, BEC and UBEC work the same. In other words, it reduces the voltage of the battery connected to the ESC to the voltage value suitable for the operation of the receiver and servos. Usually the receiver and servos support operating voltage in the 5-6V range. Some receivers and servos are suitable for 8.4 volts. But mostly ESC’s BEC/UBEC circuits provide 5 or 5.5V output. there are exceptions. It is produced in ESCs with BEC/UBEC adjustable up to 8.4V.

If the ESC does not have a BEC/UBEC feature (for example, Opto ESCs produced for drones), the receiver and servos are powered by an external power supply. An independent BEC/UBEC circuit or a battery of appropriate voltage can be used as an external power source.

An example system; 11.1V LiPo battery, an ESC with 5V BEC: