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## Chapter 16

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**Chapter 16**Additional Op-Amp Applications**Comparators**• Comparator – A circuit used to compare two voltages. • Comparators are typically used in conjunction with digital circuits. • A digital circuit is one designed to respond to alternating dc voltage levels.**Level Detector**• Level detector – Another name for a comparator used to compare an input voltage to a fixed dc reference voltage.**Integrators**• Integrator – A circuit whose output is proportional to the area of the input waveform.**RC Integrator**• An ideal RC integrator would produce the triangular (ramp) waveform. • The practical RC integrator produces the exponential waveform.**Op-Amp Integrator**• The op-amp provides a constant-current source for the capacitor, causing it to charge at a linear rate.**Differentiators**• Differentiator – A circuit whose output is proportional to the rate of change of its input signal.**Summing Amplifiers**• Summing amplifier – An op-amp circuit that produces an output proportional to the sum of its input voltages.**General-Class Equation**• General-class equation – An equation derived for a summing amplifier that is used to predict the circuit output for any combination of input voltages. • Determine the Rf / R ratio for each branch. • Represent each branch as the product of its resistance ratio and input voltage. • Write the equation as the sum of these products.**Digital-to-Analog (D/A) Converter**• Digital-to-analog (D/A) converter – A circuit that converts digital circuit outputs to equivalent analog voltages.**Averaging Amplifier**• Averaging amplifier – A summing amplifier that provides an output proportional to the average of the input voltages.**Difference Amplifier**• Difference amplifier – A summing amplifier that provides an output proportional to the difference between two input voltages. Also called a subtractor.**Instrumentation Amplifiers**• Instrumentation amplifier – A circuit used to amplify low-level signals in process control and measurement applications.**Audio Amplifier**• Audio amplifier – The final audio stage in communications receivers, used to drive the speakers.**Voltage-Controlled Current Source**• Voltage-controlled current source – A circuit with a constant-current output controlled by the circuit input voltage.**Precision Rectifier**• Precision rectifier – A clipper that consists of a diode and an op-amp. The circuit can clip extremely low-level input signals.