This circuit was found in an article in Electronics Now magazine from March 1997. The transistors are general purpose, and the indicator is a 1 mA full scale analog type.
This circuit makes use of a transconductance operational amplifier. It generates signals with TTL...
This circuit uses na Unijunction Transistor (UJT) to produce a modulation tone for several...
This circuit was found in General Electric documentation from the 1980s. The circuit uses couplers...