OP-AMP
An operational amplifier is a linear intergrated circuit that has very high voltage gain, a high input impedance and low output impedance. An op-amp can be used for a wide variety of purposes by connecting appropriate components across its terminal but mainly as smplifier. An om-amp is never used without the application of either negative ore positive feedback.
Figure below shows the symbol an om-amp
Two input terminals are provided.
- One of them labeled (-) is known as the inverting input terminal since a signal applied to this terminal appears at the output terminal with the opposite polarity, ie a sinusoidal input signal will experience a phase shift of 180⁰.
- The other input signal labeled (+) is the non-inverting input signal and signal applied to this terminal is amplified without inversion. The op-amp actualy amplified the difference between the voltage appearing at its two input terminals.
Two further terminals are provided for the connection of positive and negative power supply voltages. Two polarities are necessary so that the output voltage can vary either side of zero. Most op-amps will operate satifactory with a wide range of supply voltages.