This Schmitt optical trigger with LDR was found in old documentation. The relay must be sensitive, or an additional step must be used to trigger it.
This configuration for switching signals uses only common general-purpose diodes such as 1N4148. The...
This digital electronic game circuit was found in a 1982 publication. It randomly draws the...
This version works in the opposite way to the previous one, activating when the light falls on the...