A position input device is provided in which signals are transmitted from a position indicator, and signals transmitted from the position indicator are received by a position detector device. According to certain embodiments, an electrical double-layer capacitor, a charging circuit which charges the electrical double-layer capacitor, and a power transmission unit which relays and supplies to the charging circuit power supplied from a power supply unit external to the position indicator, are provided in the position indicator. In other embodiments the position input device has a built-in power supply unit, transmitting units, and a control unit for switching the transmitting units between energized and de-energized states. Also provided are position input systems and computer systems including the position input device, and methods of operating the position input device and the systems.