Found in an old publication, this is a transmitter with a spark coil. The high frequency oscillations of the high voltage spark generate the signal thrown at the antenna.
Suggested by Motorola documentation from the 1980s, this circuit makes use of MOSFETs of the time....
In the figure we have a small general-purpose amplifier with the LM386 integrated circuit and...
This circuit allows you to use a digital multimeter as a thermometer. The sensor is mounted in a...