051:080 Bioelectrical Design
Spring 2006
Laboratory 6 – Basic Operational Amplifier Circuits
Objective:
To learn how to build and analyze the following basic operational amplifier circuits:
1. the inverting amplifier
2. the non-inverting amplifier
3. the summing amplifier
4. the difference amplifier
Part list (per group):
• one operational amplifier
• four resistors (between 1 kΩ and 10 kΩ)
Instructions:
For each operational amplifier circuit:
• Build the circuit on your breadboard. For circuits with a single input, use a sinusoidal
waveform with a DC offset (so that you can tell whether the output is inverted or not)
as your input. For circuits with two inputs, let the second input be the 5 V DC from
the breadboard. You get to decide which of your resistors goes where!
• Analyze your circuit and determine what the output waveform should be (Consult
your lecture notes from Electrical Circuits or the lecture notes “The operational
amplifier” posted on the course web site under Supplementary Materials).
• Observe the output waveform using your oscilloscope and compare it to what you
expected. Explain any differences.
• Notice: The output of an operational amplifier is limited to its rail (supply) voltages
(in this case +/- 15 V). If you attempt to amplify a signal beyond this range, the
output waveform will be clipped at the rail voltages. If this happens, you must either
reduce the gain of your amplifier or the amplitude of your input signal.
• Qualitative: While the function generator is connected to the circuit, change the
waveform, the amplitude, the frequency and the DC offset of the input signal.
Observe the output waveform and determine whether any of these settings affects the
operation of the circuit. Describe and explain any changes you see in the output
waveform. Use sketches if necessary. (You don’t have to measure amplitudes or
frequencies.)
Revised: 02/25/2006
O. Poroy
