Solar flashlight (CB20488E)

This circuit charges a battery to power a flashlight at night. The circuit is from an English publication from 1991.

Difference Amplifier (CB6429E)
Found in a Popular Electronics of the 90s this configuration can be seen elsewhere on our site....
Two controls relaxation (CB9247E)
Found in an Electronic Design of 1964 this circuit has a control for the frequency and another for the...
8 Bit DA Converter (CB5171E)
This circuit of the 80's makes use of components of the time. The circuit is from an American...