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-
Consider the circuit below. (You may assume that the op-amps are
ideal.)
- Write an expression for the transfer function .
Express your result in terms of the amplitude of the output and
the phase relative to the input. Let k ,
, F and F. Do
not simplify the algebra.
- What are the (real) zeroes in the transfer function, if any?
- What are the (real) poles in the transfer function if any?
- Sketch the transfer function as a function of on a
log-log plot. Your sketch should show the slope of in the large and small limits, the corner
frequencies, and the value of at the corner
frequencies.
- Describe the dependence of the output on frequency at small and
large frequencies in dB/octave.
-
- Write the two rules for the analysis of circuits which utilize
``ideal'' op-amps.
- Write an expression for the potential for the
following circuit.
- Let k and k . Sketch a log-log
plot showing the function for the above
circuit assuming that a general purpose op-amp such as the 741
is used.
- The 741 op-amp has a corner frequencies of 4 Hz, DC open-loop
gain of and a fall off at high frequency of
6 dB/octave. What is the frequency domain over which the
amplifier defined in part (c) will have constant gain? What is
the gain of the amplifier in this frequency domain?
- Suppose now that the impedance is replaced with a
capacitor with a capacitance C ( k ). For
frequencies much greater than 4 Hz, the 741 op-amp will
attenuate the signal if the product RC is greater than some
maximum value. For a frequency of 50 kHz, what is the maximum
value for C for which the op-amp will not
attenuate the output signal at high frequencies? Hint: If
you sketch and , you will be
able to see the constraint on .
-
Set up an operational amplifier circuit to solve the equation
Hint: the input is .
-
Draw a schematic diagram of a circuit for which .
Specify the limitations on the input voltage range, if any.
Next: Digital Circuits
Up: Operational Amplifiers
Previous: Current Limiting and Slew
Doug Gingrich
Tue Jul 13 16:55:15 EDT 1999