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Light Bulbs and Artificial Lighting
Artificial lighting has become standard in the homes and companies of most countries. It is used for concert effects, growing food, and reading a book in bed at night.
2,482 Questions
What are chemical properties of LED light bulbs?
- the LED itself is made of what is called a binary semiconductor, different types are selected for different colors, a typical binary semiconductor used in red LEDs is aluminum gallium indium phosphide
- the lead-frame and wires are made of various alloys that are stiff, solderable, and conduct well
- the case is made typically of a transparent plastic resin off some type
- circuit boards containing other parts are made the same as other electronics circuit boards
- the outer lightbulb case that holds all this is made of about the same materials as traditional incandescent lightbulb cases are
Which is hotter a fluorescent light tube or a light bulb?
By far the hottest of the two light sources is the light bulb.
Why does a florescent light bulb ficker?
I installed spiral fluorescent light bulbs and a motion activated light switch for my kitchen light and noticed that it flickered when it was inactivated. From what I understand, the motion switch doesn't stop the current completely; it uses a small amount to run the motion sensor. That small amunt of current will build up in the flourescent bulb and discharge causing it to flicker. Fortunately, the light fixture I had held two bulbs and I simply replaced one of the two spiral fluoresent bulbs with a regular incandescent bulb and the flickering stopped. Based on that,I assume some current is still getting to yourlight bulb which is causing it to flicker.
Why are LEDs different lengths?
To make it easier to see which is positive - anode, and which is negative - cathode.
You need to know that, because the LED will only light if the positive and negative
terminals of the battery are connected to the correct sides of the LED.
This seeming contradiction occurs on most physics tests. But it's true, and here's why:
Lamp A by itself has power of P=IxE ; 60=IxE ; so I=60/220=0.27 amperes. Thus the lamp has a resistance E=IxR ; R=220/0.27 = 807 ohms.
Lamp B by itself has a power of P=IxE ; so I=100/220 = 0.45 amperes. Thus the lamp has a resistance E=IxR ; R=220/0.45 = 489 ohms.
Since the resistance in series is added up, the total resistance is 807+489 =1296 ohms and the current I= E/R = 220/1296 = 0.17.....
Phew... Since P= IxIxR
For 60W lamp A, P= 0.17 x 0.17 x 807 = 23.3 watts.
For 100W lamp B, P=0.17 x 0.17 x 489 = 14.1 watts.
So, when they are wired in series, the bright one and the dim one appear to be reversed as to their respective "normal rated powers".
Their normal rated powers are only correct when both of them are supplied with their normal rated voltage of 220 volts, i.e. when they are wired in parallel. This makes a lot of sense if you think about it.
How do florescent bulbs and ballasts work?
A ballast in a fluorescent lamp does two things: it steps up the voltage to drive the lamp, and it provides a "load" or operating resistance when the lamp "fires" and conducts. In a fluorescent application, the correct voltage for the lamp should be used, and the ballast supplies this by stepping up the line voltage. The ballast must also help with current limiting. When the gas in the fluorescent lamp ionizes and conducts, it basically forms a "short circuit" because the ionized gas presents a low resistance to the voltage source. But when the operationg current is routed through the ballast, the ballast is just basically stepping up the voltage until the lamp fires, and then when all the current tries to flow through the lamp, the windings in the ballast say, "Whoa, there, partner." This limits current. Remember that during both the positive and negative cycle of the sine wave that is driving the lamp, the lamp fires and the light comes on. For every cycle of line voltage, there are two "blinks" of the lamp.
Can plants use artificial light instead of sunlight?
yes they can use. they absorb energy from the light.
What is the different of an incandescent light and an LED light?
Incandescent Lights are basically a glass cover inside which there is an inert gas, like nitrogen, argon (low wattage ones use no gas, just a vacuum)... and there is a filament which gets heated when current passes through it... the hot filament emits light and heat... whereas an LED doesn't have gases (or a vacuum) or a heated filament... it has a semiconductor junction which emits light directly by diffusion and recombination of electrons and holes.... thus it produces less heat... and its life is much longer.
How much resistance does a 4 watt 24 volt dc bulb have?
The answer to this is a bit more complicated than you might think due to the strong positive temperature coefficient of resistance of the filament material.
When operating at its stable temperature (and voltage) this is easy to compute using Ohm's Law and the Power Formula, as follows:
- Power Formula, I = P ÷ E and solving I = 4W ÷ 24V = 167mA
- Ohm's Law, R = E ÷ I and solving R = 24V ÷ 167mA = 144Ω
- Ohm's Law, I = E ÷ R and solving I = 24V ÷ 1Ω = 24A
- Power Formula, P = IE and solving P = 24A * 24V = 576W
At intermediate temperatures the resistance will be somewhere in between these values.
It makes no difference if the bulb is powered by 24VDC or 24VAC. as AC is specified in RMS (root mean square) which is equivalent to DC. It's worth pointing out that, because the resistance of a tungsten lamp varies with variations in voltage, it is considered to be a 'non-linear' or 'non-ohmic' device, meaning that it does not obey Ohm's Law (unless the temperature is constant, but as every change in voltage changes the temperature and the temperature takes time to change following the voltage change making the actual resistance as a function of voltage very difficult to determine).
What is a similarity in the line spectrum of mercury and the spectrum of the fluorescent bulb?
A fluorescent lamp contain mercury so the identities of spectrum are normal.
Can bulbs be used in the same circuit with LED's?
If your reference to bulbs is light bulbs then yes they can be mixed. The led lamps have to be ballasted to use them in home lighting.
Perhaps moisture has worked into the headlight assembly and dulled the reflective surface. If the headlight assembly looks dulled, has any small cracks or you can see moisture inside, the assembly needs to be replaced. There are some good sources for after-market headlights and other auto-body repair parts that are far less expensive than dealerships and many are made by the same manufacturer that produced the original equipment.
What type of light helps find evidence and starts with the letter U?
ultraviolet light can be used to find fingerprints and hidden blood
How many people does it take to change a light bulb?
Usually one. For some bulbs assistance may be required. Some newer style ones don't screw in, they only twist once.
Joke Answers
- At the risk of sounding vulgar - you can't screw in a lightbulb, there isn't room.
- Three-one to hold the bulb and the other two to turn the first one holding the blub.
- Two. One to screw in the light bulb and One to hold it.
What are brighter 6000K lights or 10000K?
Neither, the brightness varies with the wattage rating not the color temperature rating.
It is called color temperature because the perceived color varies with the color temperature rating. The higher the color temperature the "whiter" the light from the light bulb. Very low color temperatures will result in red or red-orange light, medium color temperatures will result in yellow light, high color temperatures will result in pure white light, and excessively high color temperatures will result in white light with a slightly blue cast (I think 10000K will be blue-white light).
Sometimes it appears to the human eye that a pure white light is brighter than a red or yellow light of the same wattage, but this is not true when measured by a light meter.
Will fluorescent lights create more algae in an aquarium than incandescent bulbs?
Hey there, Nah it wont cause algae. If ur tank does get algae its probably because of a plant that u have in there that uve added. But that's easily fixed by adding a few drops of algae clear bought from ur aquarium.Hope that helps. Catch! :oD
Can a CMOS gate adequately drive a common LED?
You will have to check the datasheets for both the CMOS gate and the LED, then if the CMOS gate's rated output current is enough to light the LED you will need to do a little arithmetic using Ohm's law to calculate the resistor to put in series with the LED to limit current and avoid damaging the parts.
A phenomenon that causes certain materials to glow (without getting hot) when electrically excited.
