Method for identifying coin

A coin identifying method comprising:

• a reference data obtaining operation in which different types of coins are input to a coin counting device, in which a coin guider forming a coin movement path is provided, to store each of a maximum or minimum frequency value output while the different types of coins pass a first inductor of a coin identifier installed on the coin guider, a maximum or minimum frequency value output while the different types of coins pass a second inductor, and width values of linear graphs of changes in frequencies from a point in time at which a frequency changes while the different types of coins pass the second inductor until the frequency returns to a reference frequency and obtain identification reference value data for each type of the different types of coins;
• and
• a coin type and defect identifying operation in which a maximum or minimum frequency value output while a coin of the different types of coins to be identified, which is input to the coin counting device, passes the first inductor, the maximum or minimum frequency value output while the coin of the different types of coins to be identified passes the second inductor, and a width value of a linear graph of the width values of linear graphs of changes in frequencies from a point in time at which a frequency changes while the coin of the different types of coins to be identified passes the second inductor until the frequency returns to a reference frequency are compared with the identification reference value data to simultaneously determine a type of the coin to be identified and whether the coin of the different types of coins to be identified is defective,
• wherein the first inductor is mounted on the coin guider so that, according to a diameter of the coin of the different types of coins to be identified moving while in contact with one side portion of the coin guider, an area covered by the coin of the different types of coins to be identified changes, and the second inductor is spaced apart from the first inductor in a direction in which the coin guider extends and is installed on the coin guider to be more adjacent to the one side portion of the coin guider than the first inductor so that the second inductor is entirely covered by the coin of the different types of coins to be identified which moves while in contact with the one side portion of the coin guider.