LED CHANDELIER

Step 5 STEP-5

Here in this step i would like to answer some of your questions..

About Flicker:-

There is a very minimum of flicker which is not noticeable because the pair of LED's are close together.

The flicker I get is as much as a 4 feet Fl. Tube light burning.

Comments

[lauralbaby]

Could you attach a dimmer knob to this?

[phoenixdoitall]

I assume you could add a Capacitor to smooth the supply and limit the flicker if it did bother you!?

[Plaidomatic]

Because this is fully AC, not DC with an AC component, a capacitor will not do anything to reduce ficker. Some addtional changes would be necessary: change the polarity of all the diodes to point the same way, add a bridge rectifier to the output of the step-down transformer, then add a substantial amount of capacitance to reduce flicker.

[Dipankar]

Hi Plaidomatic, Changng to DC becomes costly with many addtional parts. A little un- noticeable flicker is overlooked. Your 4 ft. fluorescent tube also gives a flicker.

[Plaidomatic]

No, to change to DC you only have to add a single monolithic bridge rectifier and a single large electrolytic capacitor. A fluorescent tube does have flicker, yes, but it will be less than AC LEDs because of the persistence of the phosphor in the tube. Also, I said before, some people are rather more sensitive to flicker than others, and are even disturbed by the flicker of fluorescents.

[Dipankar]

Hi Plaidomatic, Only adding a Bridge Rectrier will not work. You have to change the circuit to DC. I don't think One capacitor will work and what about resisrors? You have said " then add a substantial amount of capacitance to reduce flicker." If you change the circuit for DC then there will be no flicker, agreed, but DC circuit costs more as you still have to have a Transformer.

[Plaidomatic]

As I stated before, changing the rest of the circuit to DC primarily requires aligning the polarity of the LEDs. No resistors are necessary. The amount of capacitance necessary would be substantial, but there are large individual capacitors that can do the job. There's nothing wrong at all with your design. I applaud its simplicity and elegance. However, should someone want to convert it to DC, I was only trying to point out that it could be done simply and with little additional expense.

[kmossman]

(removed by author or community request)

[Plaidomatic]

 Non-polar caps would be fine. Polar electrolytic caps are usually used because they provide good capacity for size/cost.

[kmossman]

(removed by author or community request)

[Plaidomatic]

This is definitely an AC circuit. Some changes to the design could refine it into two, half-wave sinusoidal DC circuits, where electrolytic caps would be useful.

[Algag]

 couldn't you just use a set of diodes(and what do ya know we have 160 right in front of us!) and wired them like such (the red is a diode the arrow shows which way the electricity can "go"

[Dipankar]

If you use a transformer to bring down the voltage then NO DIODES are required.

[Algag]

 if you used a dc transformer not the AC one you used

[Plaidomatic]

 There's no such thing as a DC transformer.

[Algag]

 what i mean is something to lower the voltage and you can get transformers that also act as inverters

[Plaidomatic]

A transformer is a magnetic component that requires an changing input to operate. A device that lowers, increases, or changes AC to DC or DC to AC is, generically, a power supply or converter.

It's best to use the correct terminology to avoid confusion.

* A single electromagnetic component that increases or decreases AC voltage is a transformer.

* A device that lowers DC voltage is a regulator, a buck converter, or, generically, a DC-DC converter.

* A device that increases DC voltage is a boost converter (also generically a DC-DC converter)

* A device that turns AC into DC is a rectifier

* A device that turns DC in AC is an inverter.

[Algag]

 ok then i am sorry for the confusion :)

[Algag]

 i frgt to tell you that the crossed wires are not connected i just made a wuick sloppy drawing

[Dipankar]

Thank you.

[phoenixdoitall]

Mmmm it was a passing thought and the answers are often explained better in the comments which I now read before leaving a comment as it gets taken the wrong way. (Spoke out loud really lol!) Moving away from this topic my concern swiftly turned to controlling the current which I know is easily achieved by converting the design to DC and as you kindly mentioned would also eliminate any flicker. Which would bother me! (Personal choice) Having learned alot about LED's and DC set ups, my comments were NOT intended to undermine Dipankar's design but left in an attempt to fully understand it and learn more about AC Circuits. I personally would NOT attempt to use any homemade LED Light AC or DC in my home without fully understanding its Concept. Many thanks Plaidomatic for your constructive answer

[Dipankar]

Make this Instructable and then see it practically, the flicker is negligible as the LED's are close together.
The flicker is more if the distance of the LED's are more.
YOU DO NOT NEED ANY CHANGE
Adding a bridge rectifier will not work on AC.
This is intentionally made for AC current.
WHY DO YOU WANT TO CONVERT IT TO DC

[Plaidomatic]

Some people are more sensitive to flicker than others. At any distance, looking at the lamp out of the corner of your eye is likely to show the flicker. While I can understand your desire to reduce part count and cost, as well as increase the simplicity of the design, the change from AC to DC is small, and eliminates any flicker. You've already used a transformer to drop the voltage to a more manageable level. Many AC-only designs even skip the transformer and use much longer serial strings of diodes. Aligning the polarity of the LEDs and adding a bridge rectifier and a smoothing capacitor are pretty trivial, if someone were building a new lamp.

[uberdum05]

You possibly wouldnt need to use four standard diodes as you have 160 of them sat in front of you :)

[Dipankar]

There is practically no flicker, as the LED's are so close together.

[DrakerDG]

Simply brilliant  :)

Regarding the flash: Each group of 10 LEDs operate in each AC cycle, 5 in the first half of the cycle and the other in the second half of the cycle. In each group, 5 LEDs are turned off while the other 5 are on and vice versa. So the time when all LEDs are turned off is rather short, with each cycle. They will be turned off during the time the voltage takes to reach the level of polarization that each LED need to begin to radiate light, otherwise 5 LEDs are lit, when the other five are turned off. That time should be fairly short, and in my opinion, the flicker can be considered negligible, and less with the fact that the LEDs are pretty close.

[zinnatty]

awesome =)

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