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 is from the time when photos were revealed in darkrooms. We found it in a 1968...
This high-gain circuit was found in an American publication from the 1990s. The circuit can use...
This circuit provides an output of 5 to 10 V at its output from inputs of 1.5 to 4.5 V. The output...