This circuit was found in a 90s Radio Electronics. It produces an ultrasonic signal in a special transducer at the frequency of 2.25 MHz. No information was given about the transformers.
This circuit locks after a short touch on the sensor. The circuit can be powered by voltages from 5...
May 2017 - Torex's XBP14E5UFN, an array of TVS circuit protection diodes with only 0.8 pF of...
This circuit triggers oscillator 555 when the supply voltage drops below the value set in the pot....