This source was originally suggested by Delco in a 1969 documentation to power amplifiers up to 50 W. The transistors are of the time admitting modern equivalents.
This thermometer, which uses common diodes as sensors, was found in a 1975 magazine -...
This circuit is from American documentation from the 70s. This configuration appears in this...
We found this Japanese commercial radio diagram of three transistors in a documentation of the...