Found in a 1964 Electronic Design, this circuit makes use of period components. The components are from the time, and modern equivalents can be used.
This circuit can generate signals from 80 to 800 Hz with an amplitude of 0.3 V. We find it in a...
We found this circuit in a Hands-On Electroncs from the 90s. The circuit uses an LED indicator. Diodes...
We found this configuration in a documentation for radio amateurs from 1974. The circuit can be...