Found in a 1967 Electronic Design, this circuit operates in a range of 0 to 1 V input with frequencies determined by C2. The components are from the period.
This circuit was found in an old publication from 1989 but can still be assembled today with BD135...
We found this circuit in a 1987 documentation. Its purpose is to turn on a garage light using the...
In the figure we have a simple logic level indicator for TTL circuits or powered by 5 V....