: The branch of physics that deals with the motion of electrons in low voltage , space , gas or solid is called electronics. The word electronics comes from the Greek word Elektron . The term elektron refers to the observation and discussion of the behavior of atoms in externally applied electrical and magnetic fields. Electronics is a branch of electrical engineering where the flow of electrons through a vacuum tube or a semiconductor device is observed. Electronic engineering is mainly used in the design and testing of electronic circuits. Electronic circuits are usually made up of registers , capacitors , inductors , diodes, etc. to perform a specific function. In 1904, John Ambrose Fleming invented a completely closed glass vacuum tube with two electrodes and was able to transmit one-way electricity through it. So it can be said that electronics started from that time.