- 1 -Grand Valley State UniversitySchool of EngineeringTechnical PaperINVESTIGATION OF THE OUTPUT VOLTAGE OF ATHREE-INPUT SUMMING AMPLIFIERTim Jousma and Jason ScholtenMarch 17, 1998I. INTRODUCTION- Background: applications of amplifiers- Motivation: exploring the effects of AC & DC sources on the output of a summingamplifier circuit- Brief description of the content of each sectionII. OUTPUT VOLTAGE IN TERMS OF INPUT VOLTAGES Derivation of Vo in terms of input voltages 2.1. output voltage for three DC input voltages 2.2. output voltage for one AC and two DC input voltages2.3. output voltage for two AC voltages having different frequenciesIII. PERFORMANCE MEASUREMENTS 3.1. Description of Apparatus- DMM to measure DC voltages, resistance, current- oscilloscope to measure AC votages, frequency with a graph- function Generator for AC inputs- CDT- various resistors, leads, op amp- 2 - 3.2 DC measurementsmeasure Vo and Vin using the sum of the three DC input voltages as Vin andfind Vsat 3.3 Gain Measurement as a Function of Frequency set Vin to a value less than Vsat to measure Vo / Vin and frequency. Use 1 AC (sine wave) input and 2 DC inputs with the peak-to-peak value taken as the value for the AC voltage.3.4 AC Measurements for Different input FrequenciesUse 2 AC inputs with different frequencies and 1 DC input. measure Vin on thescope for each source. Also, measure Vo vs t.IV. OUTPUT VOLTAGE OF THE SUMMING AMPLIFIERq Presentation of input and output voltage data - make obvious corrections and calculations needed for illustrations(more?) - present tables of measurements(raw data) - plot graphs(Mathcad and excel) – point out observations(maybe DC effect on AC output, for instance) - assign captions and titles to data and graphs - provide a sample of the raw data for readers - add narrative between figuresq Discuss relation between data and theory - compare measurements with theory - compare measured DC-only circuit outputs with calculated outputs. - no theory for second procedure(Vo/Vin vs. frequency) - compare measured Vin and Vo graphs of summed voltages with calculated Vin and Vo graphs(visual and maybe numerical analysis).- 3 -q Discuss cause for error in each circuit- discrepancies((measured – accepted) / accepted) - Discuss the value of assuming idealism in op amps. - Find the value or lack thereof in using AC sources, possibly as a consequenceof output voltage dependence on frequencyV. CONCLUSIONS- Summary and possibly suggest ways to improve or expand the work done in