Laboratory Systems for Measuring Static and Dynamic Parameters of the Basic Circuit Configurations Employing Op-Amps

This paper presents the structure and techniques for the use of two laboratory systems developed for the study of the basic small-signal DC and AC amplifier circuits employing operational amplifiers (op-amps). One of the two laboratory systems includes two electronic circuits of direct-coupled or dc amplifiers - of inverting and non-inverting configuration, and for the non-inverting configuration it is possible to set the voltage gain at different values. The second laboratory system is designed to study the two basic AC inverting and non-inverting amplifier circuits, using coupling and bypass capacitors. For both laboratory systems, a µA741C general-purpose op-amp was used as the active building component, which provides in the transition band of the frequency response a gain rolloff equal to −20 dB/decade at a unity-gain bandwidth of 1 MHz and open-loop gain 10⁵, respectively. In addition, the µA741C op-amp provides the possibility of external adjustment of the input offset voltage, which can be performed by the students. Also, the internal structure of the µA741C includes many numbers of interesting microelectronic techniques that are important to study and validate by the students during the process of experimental testing. The developed systems are intended for use in electronic studies of second- and third- year students on the Bachelor's degree programs of “Electronics” and “Mechatronics” at the Technical University of Sofia.