This analog tachometer was found in Radio Electronics from the 90s. The components used can still be found with some ease.
We found this circuit in an English publication from 1977. The circuit does not need a symmetrical power...
This circuit, from a 1988 documentation, activates a relay for a period and has a touch shutdown as...
This two-channel transmitter for the 27 MHz band was found in a recent English publication. The...