Abstract
Quality Engineering approaches have been applied in the area where electronic characteristics are used. ln some cases however, it happened that there was no reproducibility in the gain on SN ratio. In this paper, a simple transistor amplifying circuit was used to study the problem, Historically,design targets have been met through adjustment or tuning. But from quality engineering viewpoint, it is necessary to discuss the experimental techniques, circuit constants or the selection of control factors, etc. From the study, the following were concluded: (1) The characteristics of measuring equipment have considerable impact to SN ratio and sensitivity. (2) lt is necessary to consider circuit capability for the determination of the signal factor. (3)Depending on the way of setting the control factors of circuit elements, the circuit characteristics may be changed.
