The first 200 people to sign up at https://brilliant.org/stevemould/ will get 20% off an annual subscription that gives you access to the full archive of Daily Challenges and every single course. Check out Mehdi's video over on ElectroBOOM here: https://www.youtube.com/watch?v=_bgUy6zA0ts These LED bulbs will continue to draw power from the mains indefinitely even once they're switched off and the circuit is broken. But how?! You can buy my books here: https://stevemould.com/books You can support me on Patreon here: https://www.patreon.com/stevemould just like these amazing people: Glenn Watson Peter Turner Joël van der Loo Matthew Cocke Mark Brouwer Deneb Twitter: http://twitter.com/moulds Instagram: https://www.instagram.com/stevemouldscience/ Facebook: https://www.facebook.com/stevemouldscience/ Buy nerdy maths things: http://mathsgear.co.uk/