Found in Electronics now from the 90s, this circuit uses a sensor from the time, which is difficult to find today. The circuit activates a sonalert-type buzzer.
This source for devices for automotive use was found in a 1985 documentation. The power...
We found this circuit in an old Popular Electronics. It is possible to light a common neon lamp...
This circuit has an opposite action to the previous one, triggering when light falls on the...