We found this circuit in an old Popular Electronics. The circuit is experimental, driving an LED from signals applied to the LDRs. The power supply does not have to be symmetrical.
The circuit presented was obtained in a technical documentation from National Instruments. The...
This is the basic configuration of a 4 and-a-half-digit display with LEDs already containing the...
Found in a 1967 Electronics World, this circuit can use any modern equivalent FET. Observe the...