Recently I have seen some products that can swipe cards directly on the top of the screen. Aren't the bottoms of normal 5/7 inch screens made of metal? How can they swipe IC cards? Please give me some
In this circuit, the antenna (spring) is connected to the base of the first transistor. When we place the antenna near an object excited by AC current, a small current is induced into the antenna due
Definition of freewheeling diodeA freewheeling diode is a diode that plays a freewheeling role in a circuit. For example, an ordinary diode 1N4007, if you use it in a circuit to play a freewheeling ro