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.
This circuit, ideal for those who have signal problems in the UHF band, mainly in the reception of digital...
The frequency of this traditional crystal oscillator (XTAL) depends only on the used crystal,...
This is not such a sophisticated application, as it uses the two timers of a 556 in its normal...