A diode allows current to travel in only one direction. With that in mind, [Alex] built a mechanical diode that will only allow gear rotation in one direction to be transmitted through the system.

How a Virginia Tech research team constructed its novel thermal diode. Test results of the thermal diode. Electrical engineers are obviously very familiar and comfortable with the basic diode, a ...

They have created something known as an acoustic diode, that only allows sound traveling through it to go in one direction. If incorporated into building materials, such diodes would let sound ...