Abstract: A magnetic card reader comprises a card insertion slot, a magnetic head for regenerating or recording magnetic information formed on a card to be inserted in the cart insertion slot and a determining device to determine coercive force of a data track for recording magnetic information of the card. A method for determining the coercive force of a magnetic card in a magnetic card reader in which magnetic information formed on a card to be inserted from a card insertion slot is regenerated or recorded by a magnetic head comprises the steps of providing a detecting portion which detects a change in static characteristics of the magnetic head and determining the coercive force of a data track by comparing output from the detecting portion, which detects a change in static characteristics of the magnetic head while being positioned across from the card, with a reference signal.

Abstract: A magnetic head having a head unit for contacting a magnetic medium comprises at least a pair of magnetic cores which are arranged in the head unit which face each other on sides of a magnetic gap for recording and/or reproducing signals. A spacer is included for maintaining a space between one of the magnetic cores and another member, which may be the other magnetic core or a shield member. The spacer includes a usable life detection device for providing an indication of wear on the head unit which is interrupted when the head unit is worn down to predetermined depth. A device for electrically sensing an interruption of the indication is provided so that a usable lifetime of the head unit can be determined.