Chopper-type direct-current converter comprising a magnetic core, which comprises a first and a second side leg, the ends of which are connected to each other with pieces, and a center leg provided with an air gap and connected to the end pieces between the first and the second side legs. It is thus made possible to increase the stacking space, thereby increasing the number of stackable sheets and to achieve the alignment of the rear end of the sheet bundle with a simple configuration, thereby improving the stacking-aligning property of the sheet bundle on the stacking tray. The touch screen includes a computer-generated template of multiple views the vehicle, such that, the location of each paint defect can be recorded. The ceramic layer prevents a short-circuit between the positive electrode plate and the negative electrode plate, and extends along between about 40% and 90% of the length of the positive or negative electrode plate, from a winding end thereof. The present invention also provides an active matrix OLED display using the above-mentioned pixel circuit and a driving method for the pixel circuit. The nodes exchange decisions made by the intra-network node status evaluation section with other nodes and thereby identify failed node.