An active pen comprising: an elongated body member ; an elongated clip member ; said elongated body member containing therein a signal transmission module and a battery module , the signal transmission module configured to transmit a signal that is intended for detection by a touch screen comprising active digitizer technology and the battery module comprising one or more batteries to power the signal transmission module, the elongated body member comprising a control contact and a charging contact , each positioned on a surface of the elongated body member facing the elongated clip member ; said elongated clip member being connected to the elongated body member and having a free end comprising a ground contact that is connected to a reference voltage of the active pen, the ground contact being positioned on a surface , which faces the elongated body member, of the free fend, opposite the control contact and opposite the charging contact, wherein the free end is biased toward the surface of the elongated body member facing the elongated clip member to maintain the ground contact in electrically conductive contact with the control contact and with the charging contact, wherein the battery module is configured to supply full power to the signal transmission module responsive to the ground contact being in electrically conductive contact with the control contact and the charging contact, and wherein the battery module is configured to limit the supply of full power to the signal transmission module responsive the ground contact being separated from one or both of the control contact and the charging contact. an elongated body member ; an elongated clip member ; said elongated body member containing therein a signal transmission module and a battery module , the signal transmission module configured to transmit a signal that is intended for detection by a touch screen comprising active digitizer technology and the battery module comprising one or more batteries to power the signal transmission module, the elongated body member comprising a control contact and a charging contact , each positioned on a surface of the elongated body member facing the elongated clip member ; said elongated clip member being connected to the elongated body member and having a free end comprising a ground contact that is connected to a reference voltage of the active pen, the ground contact being positioned on a surface , which faces the elongated body member, of the free fend, opposite the control contact and opposite the charging contact, wherein the free end is biased toward the surface of the elongated body member facing the elongated clip member to maintain the ground contact in electrically conductive contact with the control contact and with the charging contact, wherein the battery module is configured to supply full power to the signal transmission module responsive to the ground contact being in electrically conductive contact with the control contact and the charging contact, and wherein the battery module is configured to limit the supply of full power to the signal transmission module responsive the ground contact being separated from one or both of the control contact and the charging contact. <EOS>