Suggested by General Electric in a 1968 documentation this integrated amplifier uses a component of the era, the PA237. The circuit runs on 24 V and excites a 16-ohm speaker.
In the figure we have the circuit of a simple humidity sensor with the 4011. The circuit was found...
We found this receiver for the 144 MHz band in a European publication from the 1970s. The circuit...
We found this circuit in an ancient American documentation. It can be adapted to operate in other...