Hello
I want to light a zero watt bulb with Arduino Uno. Would I need a resistor?
Please advise.
Thanks!
What is one of those?
Zero watt bulbs consume 12-15 watts of power. However, in older days, when all the appliances were turned off and only the zero watt bulb was kept on, the 'not so sophisticated' electromagnetic meter could not measure power of such less magnitude. The meter read 'zero' power and hence the name zero watt bulb.
If the bulb is powered from mains (wall) power a (mechanical) relay or solid state relay are the easiest way to switch the bulb.
I have no idea where a resistor would be used.
Something like this:
Are you wanting to control the bulb with an Arduino? Then see post #3.
Can I power the bulb from Uno itself?
No. An Uno cannot supply enough current even if it could handle the high AC voltage.
Ohh. That's sad.
The Arduino can't directly-power anything more than a regular-little LED, and those need a resistor because they are "current operated".
Lethal AC voltages MUST BE ISOLATED from the Arduino (and isolated from you, and isolated from your computer when the USB is plugged-into the Arduino).
A relay is an electrically-operated and electrically-isolated switch.
There are solid state relays that can be directly-controlled by the Arduino. This type of solid state relay is easy to wire-up. (Solid state relays can sometimes have "leakage" which means sometimes the don't completely turn-off with low-power loads.)
A regular electro-mechanical relay requires a driver circuit to power the relay coil. But you can buy a relay board that has a relay with a driver.
A relay is only on-off. Dimming is more complicated, and some LED AC light bulbs are not dimmable.
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Would this work?
Yes, it looks like a typical relay module. That said, the relays on those things tend to be pretty cheap, so if you want this think to have a long life, consider better ones.
If you're trying to control an AC lightbulb with Arduino, you must use a relay in between.
Isn't a relay module a subset of Resistor?
Hmm. To power a LED, you need a resistor in-between. For a zero watt bulb, you need a relay module in-between. And both can control the voltage.
The relay and the resistor perform different functions.
You must limit the current that flows through the LED. Something else actually powers and controls the LED.
The relay switches the power to the bulb. The inherent resistance of the bulb controls the current.
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I would very, VERY strongly advise you to not do anything involving AC given your current level of knowledge.
This stuff can kill or heavily injure you if you don't know exactly what you're doing.
Learn the basic theory first. Make sure you understand the risks involved with AC and high / voltages. Just googling some part numbers and schematics from the internet is insufficient to learn and understand the risks and which safety precautions you must take.
Good point. Any reference document for the same? I am not going back! Thank You.
I guess I will get one of these: