Solar flashlight (CB20488E)

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

Light Controlled Oscillator (CB4717E)
This circuit can function as a light alarm by changing the sound when light falls on the sensor....
Linear Sawtooth Generator (CB25678E)
Based on a unijunction transistor, this circuit was found in the January 1994 issue of Electronics Now...
Pulsing Tone Generator 4001 (CB10744E)
Although it is a common configuration today, these circuits were taken from an old publication. The...