We found this circuit in the Electronics Experimenter Handbook magazine from 1993. L1 has 2 = 2 turns of 28 or 30 wire in the shape of 0.5 cm without core. The range reaches a few tens of meters.
This ultra-low distortion driver was found in 80's Analog Devices documentation. The circuit has a...
This second-order filter was found in a documentation from the 90's. It can be implemented with...
This circuit goes into operation producing a sound on a small speaker when the supply voltage...