electrical4u.com logo Home MCQ Engineering Calculators Videos Basic Electrical Circuit Theories Electrical Laws Materials Batteries Illumination Generation Transmission Distribution Switchgear Protection Measurement Control System Utilities Safety Transformer Motor Generator Electrical Drives Electronics Devices Power Electronics Digital Electronics Biomedical Instrumentation

Inverting Operational Amplifier | Inverting Op Amp

Published on 24/2/2012 and last updated on 5/9/2018
We call the operational amplifier as an inverting operational amplifier or an inverting op-amp when the op-amp circuit produces the output which is out of phase with respect to its input by 180o.
This means that if the input pulse is positive, then the output pulse will be negative and vice versa. Figure below shows an inverting operational amplifier built by using an op-amp and two resistors. Here we apply the input signal to the inverting terminal of the op-amp via the resistor Ri. We connect the non-inverting terminal to ground. Further, we provide the feedback necessary to stabilize the circuit, and hence to control the output, through a feedback resistor Rf.

inverting operational amplifier Mathematically the voltage gain offered by the circuit is given as Where,

However, we know that an ideal op amp has infinite input impedance due to which the currents flowing into its input terminals are zero i.e. I1 = I2 = 0. Thus, Ii = If. Hence, We also know that in an ideal op amp the voltage at inverting and non-inverting inputs are always equal.

As we have grounded the non - inverting terminal, zero voltage appears at the non - inverting terminal. That means V2 = 0. Hence, V1 = 0, also. So, we can write From, above two equations, we get,

The voltage gain of the inverting operational amplifier or inverting op amp is, This indicates that the voltage gain of the inverting amplifier is decided by the ratio of the feedback resistor to the input resistor with the minus sign indicating the phase-reversal. Further, it is to be noted that the input impedance of the inverting amplifier is nothing but Ri.

Inverting amplifiers exhibit excellent linear characteristics which make them ideal as DC amplifiers. Moreover, they are often used to convert input current to the output voltage in the form of Transresistance or Transimpedance Amplifiers. Further, these can also be used in audio mixers when used in the form of Summing Amplifiers.

Related pages
Inverting Operational Amplifier | Inverting Op Amp
Please Rate this Article
5
⚑ 1 total
5
4
3
2
1


New Articles
Articles on Op-amp
Op-ampOp amp 741 ICIdeal Op AmpClosed Loop Gain Inverting Op AmpNon Inverting Op AmpOp Amp AdderOp Amp SubtractorOp Amp DifferentiatorOp Amp IntegratorOp Amp CharacteristicsOp Amp CircuitApplications of Op Amp
More Articles on Circuit Theory
Circuit and NetworkCircuit TheoremCircuit AnalysisTwo Port NetworkRL CircuitMatrixRLC Circuit
Articles Categories
Home
Basic Electrical
Electric Transformer
Electric Generator
Electric Motor
Electrical MCQ
Engineering Calculators
Video Lectures
Electrical Generation
Electric Transmission
Switchgear
Electric Protection
Electrical Measurement
Electronics Devices
Power Electronics
Digital Electronics