Electronics aim to control a flow of electrons coming from a small power source, usually batteries, to feed a light or another element (actuator) that requires energy to work.
When connecting the 2 poles of a battery with a conductor, a chemical reaction occurs and enables a huge amount of electrons to flow inside the circuit very quickly. This tends to heat up the materials up to very high temperatures, especially when the material is very thin, which enables to produce lights or heaters very easilly bu can also generated harmful burns, unwanted electric shocks or even generate disastrous fires!
More and more actuators (a.k.a. transducers) are being created and work with an appropriate power source and electronic circuit. The main goal of the circuit is to connect the power source and the actuator so as to enable a controlled and optimised flow of energy to the transducer.
Thus, one should remember that each electronic devices require the proper energy source to work efficiently, and that carefully storing power sources instead of leaving them into unused electronic devices can prevent from useless energys consumption and lower risks accidents.