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 battery-powered micropower supply was shown in Radio Electronics magazine in 1991. The...
Used by the police this receiver tuned to the low VHF band. The circuit is from a documentation from the...
This circuit was suggested by General Electric / RCA in a 1980s documentation. The components are of...