Solar flashlight (CB20488E)

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

300 Hz to 3.4 kHz Voice Filter with the 741 (CB11464E)
The circuit presented was obtained from an Electronics Now magazine from February 1995. The...
Simple Timer (CIR865E)
This simple two transistor timer can be used to measure short time intervals. The power supply...
Resistance Box (CB3900E)
This circuit allows you to program a resistance by combining the selected resistors. The circuit...