Abstract: A method of switching between groups of battery packs for supplying power to a power tool includes connecting a first group of battery packs and a second group of battery packs to a battery pack interface, discharging the first group to supply power to the power tool, and determining, using an electronic controller, a first condition of the first group. The method also includes discharging the second group to supply power to the power tool based on the first condition, determining, via the electronic controller, a second condition of the second group, determining, via the electronic controller, whether the first group has reached end of discharge, and discharging, in response to determining that the first group has not reached end of discharge, the first group based on the second condition.

Abstract: An RFID reader, tuning method and computer readable medium. A carrier signal is transmitted. A plurality of feedback signals produced in the RFID reader are measured when transmitting the carrier signal with a variable matching network set at a plurality of impedance values that are different from one another. It is determined which impedance value of the plurality of impedance values produced a feedback signal having a highest level of the plurality of feedback signals. The variable matching network is set to the determined impedance value.

Abstract: An RFID reader, tuning method and computer readable medium. A carrier signal is transmitted. A plurality of feedback signals produced in the RFID reader are measured when transmitting the carrier signal with a variable matching network set at a plurality of impedance values that are different from one another. It is determined which impedance value of the plurality of impedance values produced a feedback signal having a highest level of the plurality of feedback signals. The variable matching network is set to the determined impedance value.