A bill validator is a system that carries the currency from where it entered the system and was validated to a stack of other bills of the same value. To carry and align the bills, a 24 V forward/reverse brush motor is used. The coin machine and hopper also use a 24 V forward reverse brush motor. A sensor counts the number of coins that are being moved while a CPU controls the start and stop of the motor. The currency counter shown in the bottom right on this slide is something that might be seen when exchanging currency at an airport. A 24 V forward/reverse brush motor is used to align and move the bills so that they may be counted.