testing christmas light bulbs on a battery?

Question

How do I do this?

Answer 1

If you are wanting to test the bulbs that are connected in series on the mains, a few volts from a battery will light one.

Bear in mind that when they blow, they go short circuit so testing a bad one will short out your battery so only connect it briefly if it doesn't light. The reason they go short is to keep the rest of them on when they are wired in series.

Don't test these type of bulbs with an ohmmeter because a bad one shows low resistance same as a good one for the reason above.

Answer 2

There are two general kinds of Christmas light bulbs:
- Those designed for line voltage; these generally have screw bases, candelabra size or larger. These cannot be tested using a battery alone as the required voltage is too high; they can be tested with an ohmmeter.
- Those designed for low voltage. These generally have wire leads, and come rated for any of several different voltages. Any single cell battery will cause any of these to glow if it is good.

Answer 3

You need to determine the voltage and current requirements of the bulb and design a circuit to meet those requirements. An LED is easily destroyed by excess current or reversed polarity. The simplest and best test apparatus is a string of lights which is known to be good.

Answer 4

Make sure your battery gives enough voltage and currents to your bulbs. If the voltage too low, nothing will happen. If the voltage too high your bulbs may spoil (depend how much current the battery applies) and if the voltage is just enough and the current too low, nothing will happen too. if the current is just slight lower than demand, instability may occur and your bulb may spoil.