In an ideal op amp the open-loop gain is 103. The op amp is used in a feedback circuit, and the voltages appearing at two of its three signal terminals are measured as v2 = 0V and v3 = 2V where it is assumed that v1 and v2 are input terminals and v3 is the output terminal. The value of the differential (vd) and common-mode (vcm)signal is

Operational Amplifiers topics include: Ideal operational amplifiers, inverting and non-inverting configuration, differentiators and differential amplifiers, operational amplifiers, finite open loop gain effect, circuit performance bandwidth and large signal operations. An operational amplifier (op-amp) is a high-gain electronic voltage amplifier that has a differential input and a single-ended output. It produces an output voltage by applying an open-loop gain to the difference between the voltage at the noninverting input terminal and the voltage at the inverting input terminal.  Op-amps... Show more

Operational Amplifiers topics include: Ideal operational amplifiers, inverting and non-inverting configuration, differentiators and differential amplifiers, operational amplifiers, finite open loop gain effect, circuit performance bandwidth and large signal operations.

An operational amplifier (op-amp) is a high-gain electronic voltage amplifier that has a differential input and a single-ended output. It produces an output voltage by applying an open-loop gain to the difference between the voltage at the noninverting input terminal and the voltage at the inverting input terminal. 

Op-amps are also known as instrumentation amplifiers. They are versatile and have many uses, including as a PID/PI controller in instrumentation. They are also used in high-quality imaging applications because of their high gain. 

An ideal op-amp has the following characteristics:
No distortion
No meaningful power
Infinite amplification
No noise
Infinite input resistance
Infinite frequency response
Accepts signals of any voltage
Infinite gain
Zero output impedance 

Practical op-amps draw a small current from each of their inputs due to bias requirements or leakage. 

Here are some other types of op-amps:
Inverting amplifier: The output voltage is expressed as a function of the input current.
Summing amplifier: An op-amp configured in a specific manner. 

Related: Electronic Devices and Circuits Practice Test: Signals and Amplifiers

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