Light bulbs go on and off at the flick of the switch, at the tug of a pull chain, and when a breaker is turned to “closed” or “open”. However, the incandescent light bulb goes of far more times then most of us know. As just mentioned, when the power is not present on the electrical wire, the light bulb goes out. When power or voltage is sent to the light, it will turn on, so long as there is a bulb properly installed to the fixture.
Now, let’s consider the type of electricity that we consume in our homes. Well, it’s know as ALTERNATING CURRENT. This is the type of electricity that powers most of our homes and businesses. Direct current, currently is derived from AC current. We have drivers, converters, inverters, and transformers to help us with that part of it. Besides, the incandescent bulb cannot be powered with DC current anyways. That’s another story.
However, when we take a look at alternating current, we must take into consideration the nature of it. The keyword here is alternating.
Electrical current is depicted and measured by frequency, and sine waves.
Generally, most of our electrical devices are rated for 60 Hertz, and therefore the power companies provide us with the standard, 120/240 volts, at 60 hz.
The frequency of electricity runs like so. It rises in voltage and drops in voltage, and when we observe the sine wave that depicts this, we see that it drops to zero and even below zero. This is when the light goes out because there isn’t any power at that brief moment. It then rises to it’s full potential, only to drop again.
Therefore, the incandescent light bulb goes on and off, 60 times per second.