This automatic brightness control that uses an LDR as a sensor, was found in American documentation from the 1980s. Resistors in series with LEDs depend on the desired current.
This circuit from the 40's is a conventional analog multimeter with several scales. Its accuracy will...
The integrated circuit used in this project is no longer very common, but if found it can result in...
This switched regulator configuration was found in Motorola's 1969 documentation. The integrated...