This circuit was found in American documentation from the 1980s. The integrated circuit used is a voltage comparator of the time. Modern equivalents can be tested.
In the figure we have an application for NLAS5113, a new device from on Semiconductor...
We found this phonographic transmitter for the MW band in a 1956 documentation. The circuit has a...
The circuit shown below was obtained from an Italian magazine Sperimentare from 1977. All...