Ultrasonic: Generator

Are there some healthful positive benefits caused by being in an environment that contains negative or positive ions? Some reports suggest a wide range of benefits. This generator can be set up to generate either negative or positive ions; the builder's c

The circuit reproduces the ultrasonic noise that a male produces, this in turn repels the female mosquitoes.

The circuit uses a matched pair of 40 Khz transducer elements to detect movement up to 22 feet away. You may add a relay (not included) to switch higher voltage loads. The unit switches a LED for movement indication. Sensitivity is setable via control. Cr

Using ultrasonic techniques, this solid-state design has no moving parts.

Features a telephone ring generators, phone line in-use indicators and an audio interface circuit.