We found this circuit in an Australian documentation from 1991. The circuit is suitable for SMD mounting thus making it very small. The circuit was sold in a kit at the time.
This high selectivity circuit for single tone decoding was found in 1970s documentation. The coil...
This unusual circuit from a Popular Electronics of the 90s uses LED indicators, operating as a...
Oscillators up to some megaherts can be made with comparators like the LM139, 239 or 339. Theses...