This FM micro transmitter was found in an 80s spy book. The circuit can work with equivalent FETs and is powered by a voltage of 0.6 to 6 V. Details of the coil are given next to the diagram.
An interesting point of this project is that it is used not only for a robotics project but also...
This remote control by sound or Vox was obtained in a 2004 publication. The circuit is biestable...
This very low frequency circuit was found in a 1964 Electronic Design. Transistors may be modern...