This flip-flop circuit with general purpose transistors was found in American documentation from the 1980s. The maximum operating speed depends on the transistors. Diodes are commonly used.
This basic voltage comparator circuit has a reference voltage given by a zener diode. The input...
This interesting transistor configuration, which can be seen elsewhere on this website and in this...
This alarm goes off if someone leaves a door open. We found it in the Encyclopedia of Electronic...