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 circuit was obtained in Linear Technology documentation from 1993. The circuit provides 3.3 V and...
This circuit is from the National Semiconductor CMOS manual of 1977. What this circuit does is to...
This circuit operates from 25 to 65 kHz depending on the transducer used and the settings. We...