This circuit is from an American 1964 documentation. Transistors of the time are used, but modern equivalents can be employed.
This circuit, which appears in this section elsewhere, is from an American 1980s documentation....
The circuit is from an old American magazine EDN of 1975, but can be mounted with ease with common...
This dual circuit was found in an 80s Siliconix documentation. The power source must be...