This circuit was obtained from a 1980's QST magazine. The circuit can generate 1 to 15 MHz signals with 1 Vpp at 50 ohms load. Used transistors are still common today.
MXT1665T-A Family from Microchip Brings the User Experience of Multi-Touch HMI into the VehicleCHANDLER,...
This circuit can use a pendulum sensor. We found this configuration in a 1994 publication. The...
This unusual configuration, due to the component it uses, was found in an old European...