Found in a 90s R-E Experimenter Handbook, this circuit has a greater gain than the previous one for presenting two stages. The integrated circuit used is uncommon today.
The circuit shown in the figure generates a rectangular signal whose frequency depends on C1. For...
This circuit suggested by Texas Instruments, operates with pulses, and is based on an operational...
This circuit captures, through a coil, the signals emitted by another coil under the mat connected to...