This circuit is from a 1977 Radio Shack manual. The photocell is an LDR and the operational one is a 741. Components with non-standard values can be approximated.
This circuit is from 80s documentation, using still common CMOS components. The display is 7...
This circuit was obtained in an English magazine from 1979, but it can be easily assembled with...
Found in Electronics Now, this circuit generates signals for testing like a signal injector. The...