Abstract: A cardholder in a book form, comprising a plurality of units each having two pockets, wherein each pocket is sized to hold a card, comprises an alarm circuit in its cover or in a special compartment. Conductive strips/traces on both sides of the walls of said pockets are configured such that if the cardholder is closed while at least one of the pockets is empty, said traces creates a closed electric path between terminals of said alarm circuit and the alarm is activated. However, if the book shaped cardholder is open such that an empty pocket is exposed—the alarm is deactivated.

Abstract: A cardholder in a book form, comprising a plurality of units each having two pockets, wherein each pocket is sized to hold a card, comprises an alarm circuit in its cover or in a special compartment. Conductive strips/traces on both sides of the walls of said pockets are configured such that if the cardholder is closed while at least one of the pockets is empty, said traces creates a closed electric path between terminals of said alarm circuit and the alarm is activated. However, if the book shaped cardholder is open such that an empty pocket is exposed—the alarm is deactivated.

Abstract: A switch or circuit board having a first conductive area on a first side of the board, a second conductive area on a second side of the board, several tiny holes running through the board from the first side to the second side, and a conductive material substantially filling the holes by capillary force, where the conductive material forms an electrical connection between the first conductive area and the second conductive area.

Abstract: A board that may include for example a first conductive area on a first side and a second conductive area on a second side of such board. The board may be fitted with a plurality of holes that may for example open or end on both such first side and such second side of such board. A conductive material in the form of for example a liquid or gel may be applied or for example painted onto one or both sides of such board so that such material may for example substantially fill some or all of such holes and may establish a connection through which an electric current may pass from for example the first conductive area to the second conductive area. A switch having for example a board with a plurality of holes running through such board from a first side to a second side.

Abstract: A board that may include for example a first conductive area on a first side and a second conductive area on a second side of such board. The board may be fitted with a plurality of holes that may for example open or end on both such first side and such second side of such board. A conductive material in the form of for example a liquid or gel may be applied or for example painted onto one or both sides of such board so that such material may for example substantially fill some or all of such holes and may establish a connection through which an electric current may pass from for example the first conductive area to the second conductive area. A switch having for example a board with a plurality of holes running through such board from a first side to a second side.

Abstract: A cardholder with an alarm includes a control circuit to prevent operation of the alarm until the cardholder is folded up or closed. The control circuit is preferably an interrupted loop of conductive material on the exterior of one or more flexible pockets of the cardholder and a conductive member, which may be part of the loop, on an adjacent pocket or pockets which closes or bridges the gap in the interrupted loop when adjacent pockets are placed into overlying relationship such as by folding the cardholder.

Abstract: A credit card holder composed of a series of transparent pockets is provided with an alarm system warning the owner that a card was not returned into its pocket. Each pocket is provided with two electric contact strips attached to the inside of the pocket walls which are separated by the credit card inside the pocket and are in contact whenever the card is withdrawn. The card holder contains a battery, a buzzer and a timer suitably connected to the contact strips. This timer serves to delay energizing of the buzzer for a time period in which the transaction can be reasonably accomplished, and sounds the alarm only then.