Found in a 90s American documentation, this circuit mimics the Enterprise warning signal from the movie Star Trek. The signal must be applied to an amplifier.
Indicated by Popular Electronics to be used with a car headlight, this circuit can also have...
In this circuit of a 1970s publication, data from the coil to oscillate at the desired frequency...
This circuit was obtained from a Philips documentation from 1968. The transistors can be replaced...