Wouldn't using AC to power a lamp result in flickering?

In summary, using AC to supply power to a lamp causes it to flicker due to the constantly changing potential difference and resulting in a continuous process of giving and taking electrons. However, the flicker is usually too fast to be perceived by the human eye. The type of bulb being used also affects the flicker, with incandescent bulbs having a slower response time and LED bulbs having a sharper on/off characteristic. The choice of frequency and voltage also plays a role in the visibility of flicker. Other factors, such as the persistence of phosphors, can also impact the flicker of devices such as CRT monitors and TVs.
  • #36
jeffinbath said:
I think the silicon-iron alloys used then could have worked well at twice that frequency which would have been both good news and bad news. The good news would have been smaller lighter transformers and the bad news would have been a mains hum becoming an unpopular bumble-bee buzz everywhere.

The other bad news would be the series reactance of all transmission lines.

The Russians did a study in the 70's. They concluded that if everything started from scratch, 100 Hz would be the optimum. But nobody cared about the study because there is no thought of starting from scratch.
 
  • Like
Likes OmCheeto and jeffinbath
Physics news on Phys.org
  • #37
  • #38
I remember reading an article back around 1962 or 63 in Electronics Illustrated magazine detailing how to build a light communications project using an ordinary incandescent flashlight (PR-2 bulb) buck boosted by an audio amplifier, My brother and I cobbled together a home built amplifier and tested it using a telescope and a cut open transistor as the photoelectric element. we were able to transmit recognisable music several hundred feet. I was very surprised at the frequency response of the system,
 
  • #39
I remember many years ago (60's) at a large engineering works that machine shops had to be wired in 3 phase when lit with fluorescent lights with no adjacent
light on the same phase.This was to prevent a stroboscopic effect on rotating machinery which could make a fast rotating chuck on a lathe for instance appear stationary or slow moving.
 
  • Like
Likes Asymptotic and jeffinbath
  • #40
I once wired a resistive optical sensor in series with a 1.5V battery and the microphone input of a cheap tape recorder to search for any interesting sounds ambient light might make. It was in a city, so no matter where I pointed the thing, all I could hear was the '60 cycle' (actually 120 Hz) hum. I thought that surely the filaments of incandescents would stay hot between the half-cycles and average out the oscillating current. But turning on the indoor lights created the loudest buzz of all. Replacing the optical sensor with a plain resistor eliminated the buzz, so the source of the hum was not currents induced by the home wiring.
 
Back
Top