Then line up your 9 volt battery, with the big (negative) battery terminal on the spring, and the positive (smaller) terminal touching the button in the center of the car charger.

A smart lock is a great tool for replacing your traditional keylock with a Bluetooth-enabled lock, but can you still get in ...

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

It's possible to revive a dead cell phone by using a 9-volt battery, along with something metal like a key, and your phone's car charger. Our own Lynna Lai tested it out.

Duracell, a manufacturer of 9-volt batteries, and the National Electrical Manufacturers Association, a trade group that represents battery makers, provided these tips: 1.

In one test a paper clip resting on a 9 volt battery heated up and, in about 10 minutes, had turned a Kleenex next to it brown.

The transistor then switches on a second BC547, which lights an LED. The whole circuit is built on top of a battery clip so it can be run straight from the top of a standard 9 volt battery.

In fact, a house fire in July in New Hampshire was caused by a 9-volt battery that was stored in a plastic bag with other batteries and rubbed up against them, igniting the fire.

When a battery jumper pack is used as a memory saver, one must be very careful to not allow the disconnected positive battery cable terminal to touch vehicle metal or the negative terminal.

The investigation covers nearly 1.9 million vehicles, and NHTSA said it suspects that the problem comes from the positive terminal of the 12-volt battery shorting on the battery's hold-down frame ...