I got a little lazy, so more on that later… Next thing to do is the design of a low-battery indicator circuit for use with the homemade rechargeable 6F22 9V battery tailored for pickups and other ...

9V batteries are often found in devices that aren’t used very often. If you use a NiCd rechargeable battery you may find it completely discharged by the time you need it. Capacitors on the other ...

In this article, I will take apart a Li-ion alternative to the classic 6F22 9V battery. This battery is a Chinese 9V/500mAh USB rechargeable Li-ion battery (sold under the brand name infinite). The ...

In this case the circuit is built around a LM386 audio amplifier. It’s glued to the back of a potentiometer and wired up with the other components for a package smaller than a quarter.

With some circuits, capacitors, a speaker, and a 9-volt battery, you can build a pocket-sized theremin to create spooky sci-fi sounds.

The DIY battery pack here is essentially a USB phone charger that runs off 9V batteries, all dressed up in a fancy aluminum case (i.e., a mint tin).

6. Final Touches: Attach the 9V battery to the circuit, and your DIY USB charger is ready to use. You can now charge your USB devices on the go by simply connecting them to your new charger.

In a power outage, a 9 volt battery can give your phone enough juice to make a call or send a few texts. You may have seen this hack before , but it ...

Now I tape batteries the way I wear a seatbelt or put on a life jacket - as a common sense way of reducing risk. I just wish I'd learned it from an article instead of the fire in my friend's home.

What you need: 3 crocodile-clip wires 9V battery LEDs Assorted resistors Asparagus THE candle. It is a simple technology, and a good one. The electronic version is also simple to make, and is a ...