Title :
Capacitance measurement based on an operational amplifier circuit: error determination and reduction
Author_Institution :
Dept. of Electr. & Comput. Eng., Michigan Univ., Dearborn, MI, USA
fDate :
9/1/1988 12:00:00 AM
Abstract :
Errors introduced in an operational-amplifier-based sine-wave oscillator applied in capacitance measurement are considered. The errors due to the nonideal characteristics of the operational amplifier are addressed. The oscillator circuit was simulated using the SPICE program, and gives the opportunity to study the behavior of the circuit under nonideal conditions, and to estimate the errors introduced in the measured capacitance and the frequency of oscillation. It is shown that major sources of error are the gain-bandwidth product and the output resistance of the operational amplifier. Compensation techniques to reduce errors related to the gain-bandwidth product are presented. Experimental results confirming the error reduction are included
Keywords :
capacitance measurement; circuit analysis computing; error compensation; measurement errors; operational amplifiers; oscillators; SPICE program; capacitance measurement; compensation; error reduction; gain-bandwidth product; nonideal characteristics; operational amplifier circuit; output resistance; sine-wave oscillator; Bandwidth; Capacitance measurement; Circuit simulation; Computer errors; Electrical resistance measurement; Frequency estimation; Impedance; Operational amplifiers; SPICE; Voltage-controlled oscillators;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on