A power supply circuit includes two half bridge circuits, a controller and two terminals for connecting a motor. A coupler is rigidly connected to the first end of the housing, the housing and the coupler being separate discrete members that are connected together after formation. While allowing either one of the projector and the display unit to perform the projecting or the displaying, the processing unit causes the other one of them to perform projection or display according to detection of a predetermined operation by the detector. A particular PPP payload size greater than 1492 octets is determined. Also provided are electrolytes and batteries produced from these salts. Hard plastic, or like material, symmetric covers, with one or more pressure ports or vents, may be attached to both sides of the substrate.