We found this circuit in the 1957 Raytheon transistor application manual. The transistor can be a BC558 and the common 6 V relay, just by using this voltage in the supply.
We found this circuit in a 1971 documentation. The circuit can be assembled with more modern...
This circuit detects changes in magnetic flux in a coil as an external magnetic field moves. The...
This is a device for those who need to show that they know how to use digital electronics but have...