The post explains the construction of a homemade 100 watt capacitive tubelight circuit using 1 watt LEDs. The idea was requested, constructed, tested and verified by one the avid readers of this blog Mr. Tamam. Let's go through the entire discussion.

Discussing the Proposed The Design

At first I want to give you thanks for sharing your vast knowledge on electronics among electronic hobbyist. My name is Tamam, and I am from Bangladesh.

It was my long term wish to meet with you face to face, I was about to come in India for a personal work, but a complication in the visa process has delayed the travel plan although I still have plan to visit. 

However, I regularly visit your blog, and so far I have constructed several circuits from you blog. It's been a long time I am trying to build an AC LED Tube light which will run at 220-240 VAC and produce more or at least equivalent light as like a 60 Watt regular tube/florescent light, because I want to replace my room's tube light which annoy me always. I like LEDs very much because of their low power consumption rate and high brightness. 

I have already seen several circuits related to AC LED lights on your blog, but none are fit to my criteria.

My Requirements:""""""""""""""""1. I will use 1 Watt LED (3.3V, 10mm, 180 degree) a number of maximum 100-150 piece.2.

Power Supply will be Capacitive Type with maximum protection as far as possible. I don't want to use transformer.3. Output light has to be bright as much as a regular tube light (60 Watt) like I said above.

I know it's easy for you to design a circuit considering above requirements.Swagatam, I badly need the circuit, its my humble request to you, please take time and design the circuit for me.Sorry for my bad English & Thanks in advance !! 

My Reply: 

Thank you dear Tamam,
I appreciate your interest, I already have the requested circuit in my blog, please check out the following link:
Best Regards.

Dear Swagatam!

Thank you for your reply. Sorry to bother you bro, I don't understand "SMPS types NTC thermistor"

Even my local spare parts dealers did not understand. All they asked me for a value in Ohms for the thermistor, is the termistor compulsory for the circuit?

Because, I assembled and tested your circuit in project board successfully without the thermistor. If it is not compulsory then I wont use it.

Second Circuit:

Dear Bro, its pleasure to me after knowing that you will design and post the circuit. I always try to keep in touch with your blog. Your blog is full of electronic circuits divided into many categories, like an ocean (just kidding). Sometimes its very hard and time consuming to find new post or a particular circuit in your blog.

All I want to say that, if possible please give me the post link in email just after posting the circuit in your blog. It will be great convenience to me.

Thank You !

Thank you dear Tamam!

You can explain the dealer by saying that you want a thermistor that are normally used in 12V smps adapters. I am not sure about the exact ohms so can't suggest it correctly.

Using an Inductor as the surge Suppressor

Alternatively you can simply eliminate the NTC and use an inductor directly in series with the LED chain, this inductor could be made by winding a magnet wire (super enameled copper wire) over any ferrite core, use 100 turns of it with 10mm diameter.

The data is not critical could be a little here and there, we simply need a coil having a resistance of 10 ohms in series with the LED...that's all.


Dear Swagatam,

Thank you for providing your 100 Watt LED Circuit.

After some trial and error I have successfully built the circuit but slightly modified your circuit as below:

1. I have used total 96 nos. of 1 Watt high bright worm white LEDs.

2. I have changed the value of the AC capacitor in your circuit from 5uF/400V to 14uF / 400V (After putting total 4 nos. of 3.5uF capacitors in parallel) as I am not getting sufficient light with 5uF/400V.

I used bleeding resistor rated 1 Mega Ohms between leads of capacitors.

3. I have also changed the Filter capacitor next to bridge rectifier from 10uF/400V to 100uF/400V and added a bleeding resistor rated 470 Kilo Ohms across its output.

4. I have put a Varistor between incoming AC Neutral and Phase to the circuit.However, I am posting some images of the project. 

The following image presents PCB design layout for the above 100 watt LED tubelight circuit, Courtesy Mr. Abu Tamam.


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