Found in American documentation from the 1980s, this circuit makes use of components of the time, which are uncommon today. The circuit detects the approach using a sensor formed by metal plates.
Suggested by Motorola documentation from the 1980s, this circuit can be implemented with...
This oscillator reaches 50 MHz with an overtone crystal. The circuit is from Electronics Now...
This modulator circuit for low intensity signals is from old documentation. The integrated circuit...