This very low power circuit is based on the ICL7860. We found it in an Electronics Now from April 1995. The output current is very low.
This circuit is from an old documentation but still current for assembly. Just use BC548 instead...
We found this circuit in the Philips integrated circuits manual of 1990. The basic component is...
This low-power intercom can be powered by solar cells. The circuit is two-way, with an integrated of the...