A 9-volt battery is distinct from most other batteries. It is rectangular in shape and has hexagonal terminals on the top of the battery and is commonly used for smoke alarms. It’s not much larger than a regular AA battery but produces six times the voltage. If you want to make a light bulb light up using a 9-volt battery, then you need to ensure that the light bulb voltage is similar.
Check the label on your light bulb to ensure it can operate on nine volts. It doesn’t matter if the voltage is slightly more, it just won’t glow as bright, but if the voltage is six or less, it’s likely the bulb will blow when you connect it to the 9-volt battery.
Loosen the small terminal screws on the light-bulb holder using a screwdriver. Don’t remove them. Push or screw your light bulb into the holder.
Cut two strips of wire using a knife. Six inches should be a sufficient length. These wires will connect your 9-volt battery to your light bulb. Use wire strippers to remove about ¼ inch of plastic coating off the ends of the two wire strips.
Insert the end of one of the wire strips under one of the terminal screws on the light bulb holder; it doesn’t matter which one. Tighten the screw using the screwdriver. Repeat the process using the other wire strip.
Cut two three-inch strips of insulating tape using a knife. Place the opposite end of one of the wires from the holder onto one of the two terminals on top of the 9-volt battery; it doesn’t matter which terminal. Place the tape over the wire and terminal then fold it down the sides of the battery so it sticks in place and holds the wire on the terminal.
Repeat the process by attaching the opposite end of the other wire onto the remaining 9-volt battery terminal. Your light bulb should now light up from the energy of your 9-volt battery.