This is the traditional H bridge configuration for motors. The circuit is for currents up to 500 mA, but with higher power transistors such as the TIP31 motors up to 2 A can be controlled.
This high voltage source for gas LASER was found in documentation from the 1990s. The circuit is...
Equivalent comparators can be used on this AND gate. We found it in a Popular Electronics from the 90s. Power...
A NOR gate can be improvised using one NAND gate of a 4011 as shown here. The diodes are...