Abstract: A differential sense amplifier is described that can be configured as a preamplifier or a latch circuit as triggered by a clock signal connected to a switch circuit. When the clock signal is set at a first signal level, the switch circuit in the differential sense amplifier is activated so that the differential sense amplifier is configured as a preamplifier with a positive feedback circuit. When the clock signal is set at a second signal level, the switch circuit in the differential sense amplifier is deactivated so that the differential sense amplifier is configured as the latch circuit. For one read cycle, the differential sense amplifier operates first as the preamplifier and then as the latch circuit.

Abstract: A hinge structure for sales systems bridging a body and a display screen includes an anchor bracket fastening to the body, a first axle pivotally fastening to the anchor bracket and a second axle connecting to the display screen and pivotally running through the first axle. The first axle has two ends coupling respectively with a first axle washer. The second axle has a pivotal connecting section located on a lower side thereof to pivotally couple with second axle washers. The display screen is tiltable forwards and rearwards through the first axle, and turnable left and right through the second axle.