The operational amplifier as a laboratory tool

The ¿operational amplifier¿ as it is usually referred to in computer terminology has proved its versatility and usefulness as the backbone of modern electronic differential analyzers. In a rapidly increasing number of engineering offices, schools, and laboratories, these devices are available either in small computing installations or as separate plug-in units. It is the purpose of this paper to describe briefly their operation and to show how their usefulness may be extended beyond the usual computing applications. The applications described are suggested by a point of view which is certainly not new, but which does not seem to have been exploited to its fullest extent.