Active Elements:
Active elements are those components which can supply energy to a circuit and have the ability to amplify signals.
Examples:
Voltage Source ( Batteries, Power supplies), Current Source, Transistors (BJT, MOSFET), Operational Amplifiers (Op-Amps).
Passive Elements:
Passive elements are those components which cannot generate energy. They consume or store energy in the form of heat, magnetic fields or electric fields.
Examples:
Resistor, Capacitor, Inductor, Transformer ( does not generate energy only transfers ).
