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

fYear

1990

fDate

28-31 Aug 1990

Firstpage

253

Lastpage

260

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;

fLanguage

English

Publisher

iet

Conference_Titel

Electromagnetic Compatibility, 1990. Seventh International Conference on

Conference_Location

York

Print_ISBN

0-85296-001-8

Type

conf

Filename

98064