Use in reference to electronic speed controllers, used with both brushed and brushless DC motors on drones and model aircraft.

ESCs for brushed motors are often built using an H-bridge circuit to enable the motor to rotate in two directions but by the nature of needing to electrically commutate, ESCs for brushless motors have a "Three-Phase H-Bridge" circuit and more involved circuitry to detect the rotational position of the BLDC motor.