Title :
Undergraduate student projects on determining demodulation RFI statistics for operational amplifiers
Author :
Ghadamabadi, H. ; Whalen, J.J. ; Chan, K.H. ; Coslick, R.T., Jr. ; Johnson, T.S. ; Sitzman, W.B. ; Stevens, J.S.
Author_Institution :
State Univ. of New York, Buffalo, NY, USA
Abstract :
A team of five undergraduate Electrical Engineering students under the supervision of a graduate student have measured RFI effects in an inverting operational amplifier (op amp) circuit with a voltage gain equal to ten for two sets of input and feedback resistor values. For the first case, the input resistor R1 is 10 kΩ, and the feedback resistor R2 is 100 kΩ. For the second case, R1 is 0.1 MΩ and R2 is 1 MΩ. Measurements were made with and without the RFI suppression capacitor C2=27 pF shunting R2. Each student was assigned 25 to 30 op amps of one type. The five op amp types tested and their input transistor type are the following: (1) 741 (bipolar NPN); (2) LM10 (bipolar PNP); (3) LF355 (JFET); (4) CA081 (MOSFET); (5) OP27 (NPN bipolar)
Keywords :
bipolar integrated circuits; demodulation; electric noise measurement; field effect integrated circuits; operational amplifiers; radiofrequency interference; resistors; 0.1 Mohm; 1 Mohm; 10 kohm; 100 kohm; 27 pF; JFET; RFI measurement; RFI suppression capacitor; bipolar NPN; bipolar PNP; demodulation RFI statistics; feedback resistor; input resistor; input transistor; inverting operational amplifier; undergraduate student projects;
Conference_Titel :
Electromagnetic Compatibility, 1990. Seventh International Conference on
Conference_Location :
York
Print_ISBN :
0-85296-001-8
