This 12 V x 2 A regulator was found in 1965 Delco Radio documentation. The circuit uses transistors from that time. The input voltage can vary by 15% around the indicated value.
This filter, which rejects frequencies around 1 kHz, was found in the August 1993 Electronics Now...
The LM1468L can also be used. The circuit is from Motorola's Linear Interface ICs and the...
We found this logic level tester in a 1976 documentation. The circuit is powered by the voltage of the...