This circuit was obtained in a documentation from the 80's. However, using TTL it is still modern, being able to be used as Shields for microcontrollers or part of digital projects.
This stage was used in old audio ampliiers and radios from the 1950s and 1960s. It uses one of the...
Found in a 90s R-E Experimenter Handbook, this amplifier uses an integrated circuit from that...
We find this circuit in an American 1980s documentation. The unijunction transistor may be the...