Ok so recently I had a free day and found a few spare Christmas lights laying around so I decided to try and light one up using batteries. I ended up being successful and attaching the light to a mini Christmas tree I have in my room.
(click to view large)
It's nothing much and it's pretty dull, but I didn't dare add more batteries in case I burnt out the bulb, I don't actually know how much power the bulb can take as it is stated nowhere. To light the bulb up I connected three 1.5 volt batteries in series, making the total potential difference of the circuit 4.5 volts, however it is probably lower due to the batteries being run down.
These are the batteries crappily attached together (click to view large)
Just now I have had the idea of connecting the bulb to a USB port on my computer, but I don't know whether to go ahead with the idea. I have a spare phone charger cable which I can cut and connect to the bulb, and USB ports only provide a bit more power than the batteries in series (which means the light probably won't burn out) but I am afraid if there are hazards to doing this. If raw cable comes in contact with a conductor while plugged into the computer, will my USB port/other components get damaged? What if the bulb consumes a lot more power than I thought? Will it cause damage? May I need to attach a resistor to the circuit? Do I need to cover the raw cables?
Advice would be much appreciated. I don't want to do something that can cause problems.
