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 can be used as a shield as long as the power is supplied with voltage equal to that...
This simple megaphone is from old documentation, but uses still current components. The circuit is...
This simple telephone amplifier can be used as an auxiliary amplifier for additional listening, without...