Vegemite is an infamous condiment spread that Australians pretend to like as some sort of prank on the rest of the civilized world. It is, of course, not safe for actual human consumption. But apparently it’s a pretty good electrical conductor. That means you can make Vegemite-on-toast circuits, as proven by Luke Weston’s viral tweet.
Luke Weston is, you guessed it, Australian, and that means he was bequeathed with a large volume of Vegemite by his government — a right granted to all Australian citizens. He obviously wasn’t going to eat the stuff unless foreigners were around to watch, so he decided to use it for a far more practical purpose instead.
That purpose was a circuit to light up an RGB LED. Weston applied traces of Vegemite on a piece of toast, which connect to the legs of the LED. This appears to be a common anode LED, with one Vegemite trace going from the anode to the positive side of a DC power source, and three traces leading away from the cathodes. By connecting those cathode Vegemite traces to the power supply’s negative side, Weston could light up the LEDs in different colors! Sure, it’s just an LED, but it’s a far better use for Vegemite than as food.