# Op Amp Characteristics

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Date Submitted: 08/30/2011 07:48 AM

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OP-AMPS Characteristics:

Objective

To define the meaning of common op-amp specifications and determine the op-amp characteristics. In this experiment we have to measure the input offset voltage, input bias current, input offset current, and common-mode rejection ratio.

Materials

* 741C Op-Amp

* Resistors

* Capacitors

* One Solderless Breadboard (if needed)

Theory

There are hundreds of types of operational amplifiers that are available. Operational amplifier is a linear integrated circuit has a DC-coupled, high-gain differential amplifier and there are many different circuits that can be made for different purposes. We will be looking at many different characteristics like the Common-Mode Rejection Ratio (CMRR) which measures the behavior of the device that rejects input signals common to both input leads. A op-amp can either be inverting or non-inverting amplifier depending on if its on negative (inverting) or positive (non-inverting). There are also power supply connections in a amplifier which don’t have to be used if not needed. Basically the negative and positive symbols on a amplifier is where the input will be going through and the output will be indicated on a amplifier so you can measure or add another circuit of your desire.

Procedure

* We first measured all the resistors and recorded them on to the table provided.

Resistor | Listed Value | Measured Value |

Rf | 1.0 MΩ | 97.7 kΩ |

Ri | 10 kΩ | 9.7 kΩ |

Rc | 10 kΩ | 9.73 kΩ |

* We connected the circuit shown below and measured the output voltage. The input offset voltage can be found by dividing the output voltage by the closed loop gain (AV(CL) = Rf/Ri + 1. Record the measured VOS in the table on the next page.

* For the next part we measure the resistors needed for this circuit and connect the circuit shown below.

* We then measured the voltage across R1 and R2 and calculate the current using Ohm’s Law.

Resistor | Listed Value | Measured...