A currency detector is a device that determines if a piece of currency is, or is not, counterfeit. Currency detectors are used in vending machines that accept payment and dispense a product to a customer. They are also used in change machines and in slot machines. The basic process involves looking at the currency that has been inserted and by using various tests, determine if the currency is counterfeit. Since the parameters are different for each coin or paper money, these detectors must be programmed for each item that they need to accept. In operation, if the item is accepted it is retained by the machine and placed in a storage device. If the item is rejected, the machine returns the item. If it is a coin, it usually drops into a container for the customer to take back. If it is a bill, the machine pushes the bill out and the customer must remove it from the slot in which it was placed.
