This circuit is from a 1966 NASA documentation. The circuit uses a photodiode as a sensor. The other components are from that time.
This circuit was found in an Electronics World of 1969. Transistors are general-purpose types. It...
It is like to the previous circuit with a lock that keeps the LED on at the end of the timer. The...
This good quality audio amplifier with an output of about 10 W with the original transistor was...