The picture below illustrates the components of a LED (light emitting diode) flashlight and steps on how to use it.
Overall, it is evident that there are 4 main features, including the batteries to make the flashlight work, as well as a circuit to control its power.
Firstly, this device has a small LED bulb, a metal string, and a flow of current going through two batteries and passing the metal switch contacts, which are operated inside a plastic case. Moreover, this gadget also contains a switch outside the case where users can use its button to turn on and off.
Moving on to its operation, when the flashlight is switched on, the button circuit that connects with the metal switch contact will let the electricity from the two batteries flow through and reach the LED light. By contrast, as users switched back to off, the circuit should be broken and the line is detached. As a result, the energy from the batteries will be cut off and the bulb will no longer emit light.