This highly sensitive light sensor was found in a 1970 General Electric documentation. The circuit can use the 2N2646 for the UJT and the phototransistor can be of any type.
This is the receiver for the previous circuit we found in the December 1992 Radio Electronics...
We found this configuration with CMOS-compatible output in the 1994 National Semiconductor Linear...
This 70 kHz oscillator is used to erase tapes in pre-recording. The circuit is from 1968 General...