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Designing An Opamp Headphone Amplifier

Logatithmic Amplifier

Opamp Classes And Major Characteristics

Opamp AC Specifications

Opamp DC Specification

The µA748 OPAMP

The LM101A OPAMP

The LM101 OPAMP

The µA709 Opamp

OPAMP History

Phase Shift Oscillator

The Ideal Opamp

Opamp Output Impedance

Opamp Input Impedance

Opamp Voltage And Current Offsets

Opamp Negative Feedback

Opamp Active Filters

Integration Circuit Amplifier

OPAMP - Differential Amplifier

Opamp Current Summing Amplifier

OPAMP Inverting Amplifiers

Non-inverting Amplifiers

Powering Up The Op-Amp

741 Op-amp Pin Functions

741 Op-amp Pin Diagram

741 Opamp Internal Block Diagram

Opamp Absolute Max. Parameters2

Open-Loop Gain & Frequency

Absolute Max. Parameters

What Is An Op-Amp

30 topics total

Logatithmic Amplifier

Opamp Classes And Major Characteristics

Opamp AC Specifications

Opamp DC Specification

The µA748 OPAMP

The LM101A OPAMP

The LM101 OPAMP

The µA709 Opamp

OPAMP History

Phase Shift Oscillator

The Ideal Opamp

Opamp Output Impedance

Opamp Input Impedance

Opamp Voltage And Current Offsets

Opamp Negative Feedback

Opamp Active Filters

Integration Circuit Amplifier

OPAMP - Differential Amplifier

Opamp Current Summing Amplifier

OPAMP Inverting Amplifiers

Non-inverting Amplifiers

Powering Up The Op-Amp

741 Op-amp Pin Functions

741 Op-amp Pin Diagram

741 Opamp Internal Block Diagram

Opamp Absolute Max. Parameters2

Open-Loop Gain & Frequency

Absolute Max. Parameters

What Is An Op-Amp

30 topics total

One of the practical op-amp limitations is that there is a finite output impedance. For the 741 it is about 75 ohms but can be as high as several thousand ohms for some low power op-amps. The effective output impedance is further lowered by the use of negative feedback, so the focus becomes not one of the number of ohms looking into the output, but what limitations are placed on the output current.

Limiting the output current also limits the allowable output voltage swing: the lower the load resistance, the lower the allowable voltage amplitude. For a load >2K, the 741 can swing to within about 2 volts of the supply.

This is about all that is permitted by common mode limits for a 15 volt supply so the output impedance is not a serious limitation. For lower load impedances, however, the safe output voltage swing will be progressively curtailed. Op-amps with MOS transistor outputs(CA3130 and CA3160) can swing all the way to positive and negative supply voltages.

Keywords : Opamp, Op-amp, output, Voltage, Input, Impedance, Offsets, Amplifier, Amplificator, Amplification

13 Mar 2006 Mon

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