This code practice circuit was found in a 1990s issue of Radio Amaterur Today magazine. It produces an audio tone with the 555.
With this relaxation oscillator with a neon lamp we can generate small intensity audio signals for...
This setting appears elsewhere on this site. This was obtained from an 80's Circuit Encyclopedia and...
This circuit produces a sine 1 kHz signal. The frequency is given by C1, C2 and C3. This is a...