Found in documentation from the 1980s, this circuit can generate signals between 6 and 8 MHz. The frequency can be slightly varied in the setting. FET is a general-purpose type.
I found this circuit in a 1980 documentation, but it can be easily assembled with BC548...
We found this alarm in an English publication from 1978. Although the original power supply is 3...
Found in old documentation, this circuit can use modern equivalent components. The signal has good...