Is An AC Light Bulb Better Or A DC Light Bulb ? - Please Tell Me

April 15, 2015 5 Comments

ac light bulb vs dc light bulb

What’s The Difference between AC and DC Lighting and Light Bulbs?

Lets start off by making it clear to everyone , both voltage are for different application and has its own usefulness , so they should not be compared as they serve different purposes.

The terms AC and DC ( Alternating current and Direct current ) , are terms that everyone has learnt in their high school science classes. But when it comes to light bulbs, what is the difference between AC and DC lighting and light bulbs? To get a better understanding at this, we can go ahead and  get a recap on what exactly is AC and DC.

The magnitude and direction of an alternating current changes while that of a direct current remains in the same direction. Alternating current is the form in which businesses and residences
receive their supply of electricity. In alternating type of current, the current in the circuit constantly goes back and forth. The alternating current is supplied by a power plant. All residences typically have alternating current delivered to them by a substation which is fed by the power plant. The direction of the alternating current switches back and forth 50-60 times per seconds. This is known as the hertz (hz). The hertz is the reason why a light bulb appears to be glowing constantly, in spite of the current switching back and forth so many times.

AC voltage also allows us to use a magical device called a transformer, the transformer allows us take in voltage and current on one line, then output a different voltage and current with the same total power ( watts ) on another line. We can not do this efficiently with DC power. So  AC power is utilized because it;s voltage can be stepped up to super-high levels, and drop the current to a trickle. Making it ideal for long distance transmission.

Using alternating current saves power because it uses a higher voltages to send smaller currents, which also significantly reduces heating in wires, which is known as resistance. Transformers can convert a current that is high voltage into a current that is low voltage and vice versa. Alternating current is even faster to travel when it is high voltage, which is why transformers increase the voltage when the current is sent and other transformers decrease the voltage before it is redirected to houses and businesses. Direct current can also be used in lighting and bulbs but a lot of power is expended as well a lot of effort to send it to distances that are far away. Let's put it this way, DC current in low voltage cannot travel very far without losing its power. Further away it has to travel, the thicker the wiring is required. Which can become very costly.

DC - Direct current, on the other hand, comes from battery sources, bridge rectifiers, solar panels, cars , boats , etc. The current is made to go through conductors as well as semiconductors and insulators. Wires are an example of conductors. Direct-current wiring is usually one red one black with red being positive and black being negative.

All electricity distribution the world over uses alternating current because of its many advantages with regards to transmissions and the use of transformers. If direct current is required, then the alternating current that is distributed to a substation is converted into a direct current.

In a light bulb, the filament in the bulb acts as a resistance to the electrons that otherwise flow without impediment through the wire. Although the electrons can still pass through the filament, just like they pass through the wire, this requires more effort on their part. It is this work that the electrons have to do to overcome the resistance caused by the filament that generates heat that makes the filament light up.

If an electrical device can convert AC to DC and vice versa, it does not matter what type of current is supplied to it. For light bulbs and heating elements, both AC and DC will work as long but the fact is that though all electric devices require direct current, alternating current is what is used to deliver electricity with the help of transformers which convert AC to DC for the use of electric devices.

So in a nutshell , AC household light bulbs are good for household use where almost all electricity is supplied by providers that utilize a AC current. DC light bulbs are good for remote and self standing power supplies , such as DC batteries , cars , boats , yachts , solar off grid systems , trains , airplanes and more. The distance between the power source and the light itself is not too far and power can still be distributed without a large loss. 


5 Responses

Ajit Patra
Ajit Patra

June 02, 2020

Plz ans me different between ac24V bulb and dc 24v bulb..

Luis Acosta
Luis Acosta

November 07, 2018


Im interested in purchasing some items in your facility but firstly i we like to know if this possible

1:can you send to Panama
2:Do you accept private pick up
3:Do you have POS machine to charge credit card and accept master and visa credit card payment ?

Kindly email me if this is possible with out any i can send you the list of items i wanted to purchase

I will await your reply Asap,

Best Regards

Luis Acosta
Acosta Supply Inc


November 06, 2017

Could you power a 220vac electric heater with 110v.
Of course getting far less heat, and of fan motor is 220v, much slower airflow?


March 23, 2017

If my knowledge is correct you would need a 24v light bulb in order to produce the same amount of power the bulb is intended to be rated for. P=IV and also V=IR so in order to maintain the same wattage of power the resistance of the bulb would otherwise be greater on the 24v bulb. P= (V^2)/R. Sure if you plug in a 12v bulb on a 24v system itll be brighter due to the less resistance therefore greater output of power. IF the bulb does blow out right away. The filament will produce so much power it might melt itself from excess heat. Let alone have an appropriate lifespan. Heat is a biproduct of resistance. (How electric heaters also work). Usually on DC bulbs it is printed what voltage is it rated for, for best output and lifespan guarranteed by the manufacture. Sorry for the long response but it is explained so that one can fully understand. 4th semester engineering student and I work as a mechanic. I learn a lot in school and at work they go hand in hand!


December 07, 2016


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