Op-Amp Circuits The center frequency of a band-pass filter is always equal to the bandwidth –3 dB frequency bandwidth divided by Q the geometric average of the critical frequencies The formula shows that for a given capacitor, if the voltage changes at a constant rate with respect to time, the current will increase decrease be constant decrease logarithmically A digital-to-analog converter is an application of the scaling adder voltage-to-current converter noninverting amplifier adjustable bandwidth circuit If the value of resistor R_{f} in an averaging amplifier circuit is equal to the value of one input resistor divided by the number of inputs, the output will be equal to the average of the individual inputs the inverted sum of the individual inputs the sum of the individual inputs the inverted average of the individual inputs If the input to a comparator is a sine wave, the output is a rectangular wave sawtooth wave ramp voltage sine wave A basic series regulator has an error detector a reference voltage a load both an error detector and a reference voltage A comparator is an example of a(n) linear circuit nonlinear circuit current source active filter Initially, the closed-loop gain (A_{cl}) of a Wien-bridge oscillator should be 0 Acl < 3 Acl > 3 Acl 1 In an averaging amplifier, the input resistances are equal to the feedback resistance less than the feedback resistance greater than the feedback resistance unequal A zero-level detector is a comparator with a sine-wave output comparator with a trip point referenced to zero peak detector limiter Time's up