This is the basic configuration of an operational amplifier sample & hold circuit. The FET and transistor are commonly used. The circuit is from an 80's documentation.
We found this circuit in a 2001 publication. It sequentially drives Laser Pointers at a speed that...
This flip-flop controlled by an LDR-type photocell was found in Radio Electroinics magazine from...
The presented circuit makes use of operational ones that are not common in the market. More modern...