(1) Using a double pole double throw switch is the simplest method.
Connect the positive and negative poles to the input terminals of the switch, connect the negative and positive poles to the output terminals, and connect the load to the moving contact.
(2) Use a small relay or contactor with a capacity equivalent to the load, and the connection method is the same as (1).
Use a switch or circuit to control the on and off of the small relay's wire package, which can easily realize automatic control.
The words switch mean on and off. It also refers to an electronic component that can open a circuit, interrupt current, or cause it to flow to other circuits. The most common switch is a human-operated electromechanical device that has one or several electronic contacts. The "closed" state of the contact means that the electronic contact is conductive, allowing current to flow; the "open" state of the switch means that the electronic contact is not conductive, forming an open circuit, and does not allow current to flow.