The circuit presented was suggested by Texas Instruments in an opto-electronics manual. The transistor can be the BC548 and the supply voltage depends on the application.
This circuit was found in a 1967 Raytheon manual. The transistors are from the time. Equivalent modern...
This circuit was published in a 1979 magazine, but it can still be easily assembled as the...
The circuit presented generates short pulses. This configuration was found in a publication from...