I've been fascinated with joule thief circuits since I made my first one. It's amazing what all you can power from a single AA or AAA battery. The only problem is you can't do much beyond light up an LED because the current isn't "always on". With a couple of extra components, you can take your joule thief to the next level! While this circuit isn't particularly useful other than draining dead batteries, it's a good starting point for building more advanced circuits powered by a joule thief.
Read more at [ hackster.io ].