## APPLICATION OF OP AMP

Table of Contents

**APPLICATION OF OP AMP**, **1. PHASE SHIFT CIRCUIT**, **2. Phase lag circuit**

### APPLICATION OF OP AMP

An op-amp is used in the Fundamental Inverting Amplifier Configuration, which has input Impedance Z1 and Feedback Impedance Zf.

If the Impedance Z1Â Â and Z*f*Â Â are equal in Magnitude and phase, then the closed loop voltage gain is -1,and the input signal will undergo a 180^{0}Â phase shift at the output. Hence, such circuit is also called phase Inverter. If two such Amplifiers are connected in cascade, then the output from the second stage is the same as the input signal without any change of sign.

Hence, the outputs from the two stages are equal in Magnitude but opposite in phase and such a system is an excellent Para phase Amplifier

According to the above diagram, the closed loop gain is -k, the input voltage is Multiplied by a factor of -k, and the scaled output is available at the output if the ratio Zf/Z1 = k, a real constant. Zf and Z1 are typically chosen as Precision Resistors in these applications to obtain precise and scaled input voltage values.

**1. PHASE SHIFT CIRCUIT**

The phase shift Circuit maintain a constant gain while producing Frequency-dependent phase shifts. All-pass or Constant-delay filters are other names for these circuits. When a frequency is changed across a range of operating Frequencies, the time delay between the input and the output remains constant.

Because a constant gain is Typically Maintained for all Frequencies inside the operating range,. This is known as an all-pass system. For lagging phase angles and leading phase angles, there are two different types of circuits.

**2. Phase lag circuit**

Phase lag circuit is Constructed using an op-amp, connected in both inverting and non-inverting modes. To analyze the circuit operation, it is assumed that the input voltage v1 drives a simple inverting amplifier with inverting input applied at(-)terminal of op-amp and a non-Inverting amplifier with a low-pass filter.

It is also assumed that inverting gain is -1 and non-inverting gain after the low-pass circuit

According to the above, the relationship is complex and it can be seen that it has both Magnitude and phase. Complex conjugates in the denominator and numerator make their