Operational Amplifiers, also known as Op-Amps are electronic integrated circuits which amplify weak electrical signals to strong signals. They generally have two input terminals and one output terminal. They can also perform various different functions such as eliminating unwanted noise and frequencies from the input signals. Op-Amps are used with resistors and capacitors to form different types of circuits which can perform different tasks, The main purpose of Op-Amps is to generate larger output signal from an input signal.

Further below we will see more information about Op-Amps in detail, as well as their types and applications.

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- What is Operational Amplifier (Op-Amp)?
- Characteristics of Operational Amplifier (Op-Amp):
- 1. Input Resistance:
- 2. Output Resistance:
- 3. Offset Voltage:
- 4. Offset Current:
- 5. Input Impedance:
- 6. Output Impedance:
- 7. Voltage Range:
- 8. Open Loop Voltage Gain:
- 9. Common Mode Gain:
- 10. Noise:
- 11. Bandwidth:
- 12. Drift:
- 13. Power Consumption:
- 14. Effect of Temperature:
- 15. Slew Rate:
- 16. Power Supply Rejection Ratio (PSRR):
- 17. Common Mode Rejection Ratio (CMRR):

- Types of Operational Amplifier (Op-Amp):
- Comparison Between Ideal Op-Amp and Practical Op-Amp:
- More:

*What is Operational Amplifier (Op-Amp)*?

Operational Amplifiers, also known as Op-Amps are electronic integrated circuits which amplify weak electrical signals to strong signals. They generally have two input terminals and one output terminal. They can also perform various different functions such as eliminating unwanted noise and frequencies from the input signals. Op-Amps are used with resistors and capacitors to form different types of circuits which can perform different tasks, The main purpose of Op-Amps is to generate larger output signal from an input signal.

*Characteristics of Operational Amplifier (Op-Amp):*

### 1. *Input Resistance:*

Input Resistance is the resistance at the input terminals of an Op-Amp.

### 2. *Output Resistance:*

Output Resistance is the resistance at the output terminals of an Op-Amp.

### 3. *Offset Voltage:*

Offset Voltage is the voltage which is necessary to be applied at input terminals of an Op-Amp to get zero volts at the output terminals.

### 4. *Offset Current:*

Offset Current is the difference of input bias currents and practically the difference between them is not zero.

### 5. *Input Impedance:*

In Operational Amplifiers the input impedance is specified by two ways:

#### a. *Differential Input Impedance:*

Differential Input Impedance is the total resistance between the inverting and non-inverting inputs of an Op-Amp. It is measured by determining the change in the bias current for a given change in the differential input voltage.

*b. Common Mode Input Impedance:*

Common Mode Input impedance is the resistance between each input terminals and ground terminals of an Op-Amp. It is measured by determining the change in the bias current for a given change in the common mode input voltage.

### 6. *Output Impedance:*

Output Impedance is the resistance observed from the output terminals of an Op-Amp.

### 7. *Voltage Range:*

Voltage Range is the range within which the operational amplifiers works properly. The input voltage range and output voltage range may differ from each other in value.

### 8. *Open Loop Voltage Gain:*

Gain is a ratio of output to the input of the circuit. A gain with no feedback is known as Open Loop Gain. Open Loop Voltage Gain is the ratio of change in output voltage to the change in voltage at input of an Op-Amp.

### 9. *Common Mode Gain:*

Common Mode Gain is the voltage gain of the common voltage between the two input terminals of an Op-Amp.

### 10. *Noise:*

Noise is an unwanted signal/disturbance that interferes with the operation or the original signal of an Op-Amp.

### 11. *Bandwidth:*

Bandwidth is the frequency within which the Op-Amp works or can work.

### 12. *Drift:*

Change in performance of an Op-Amp due to change in temperature is called as Drift.

### 13. *Power Consumption:*

Power Consumption is nothing but the total power used by an Op-Amp.

### 14. *Effect of Temperature:*

Variation in temperature creates changes in the functioning and behavior of an Op-Amp.

### 15. *Slew Rate:*

Slew Rate is the maximum rate of change in the output voltage in due to change in step input voltage.

### 16. *Power Supply Rejection Ratio (PSRR):*

Power Supply Rejection Ratio is the ratio of change in supply voltage with respect to the change in input offset voltage. The PSRR is a characteristic of Op-Amp which helps in rejecting any fluctuation or change in power supply voltage.

### 17. *Common Mode Rejection Ratio (CMRR):*

Common Mode Rejection Ratio is the ability of Op-Amp to reject or moderate the common signal at the inputs of an Op-Amp. It is the ratio of common mode gain to differential mode gain. CMRR helps in reducing noise or unnecessary signals.

*Types of Operational Amplifier (Op-Amp):*

There are two types of Operational Amplifiers:

*1. Ideal Operational Amplifier.*

### 2. *Practical Operational Amplifier.*

Lets see explanation of the Ideal Op-Amp and Practical Op-Amp in below comparison.

*Comparison Between Ideal Op-Amp and Practical Op-Amp:*

SR. NO. | Parameter | Ideal Operational Amplifier | Practical Operational Amplifier |
---|---|---|---|

1 | Explanation | Ideal Operational Amplifiers are perfect amplifiers with 100% efficiency and they are not affected by any material, design or parameter in an electrical circuit or enviroment. The concept of Ideal Op-Amps is simply theoretical | Practical Operational Amplifiers are actual amplfiers which are available practically and are affected by various different material, design and environmental flaws. These are the amplifiers we use in real world scenario. |

2 | Input Resistance | Infinity ∞ | High |

3 | Output Resistance | Zero 0 | Low |

4 | Offset Voltage | Zero 0 | Low |

5 | Offset Current | Zero 0 | Low |

6 | Input Impedance | Infinity ∞ | High |

7 | Output Impedance | Zero 0 | Low |

8 | Input Voltage Range | Infinity ∞ | Finite |

9 | Output Voltage Range | Infinity ∞ | Finite |

10 | Open Loop Voltage Gain | Infinity ∞ | High |

11 | Noise | Zero 0 | Low |

12 | Bandwidth | Infinity ∞ | Low |

13 | Drift | Zero 0 | Low |

14 | Power Consumption | Zero 0 | Low |

15 | Effect of Temperature | Zero 0 | Low |

16 | Slew Rate | Infinity ∞ | finite |

17 | Power Supply Rejection Ratio (PSRR) | Zero 0 | finite |

18 | Common Mode Rejection Ratio (CMRR) | Infinity ∞ | High |