The jumper cap is also called the short circuit cap. The short circuit block is a small square plastic cap on the main board, hard disk and other hardware, and its interior is metal.

For example, if a single row of pins is used, the two adjacent pins can be short-circuited with a short circuit block, that is, the connection on the circuit can be realized.

For example, there is a three-wire contact pin and a short circuit block can realize the function of dial switch. It is used to connect the pins of the peripheral module and the pins of the microcontroller. After the short circuit cap is removed, the single chip microcomputer pin is not connected with any module. The function is to change the circuit. The voltage drop caused by the metal connecting wire used to connect the two demand points of the circuit board (PCB) changes the performance.