# A power supply circuit from 220VAC to 5VDC 1A or 1.5A

#### q12x

Joined Sep 25, 2015
747

I have a led lamp that I really like.
It was originally design to work on USB but I adapted it to work from a 5V power supply. All the adaptation I did to it, was to take out the usb, drag the wires out and connect them to my 5V power source. I install it to my electrical drill and to a 3 way switch. Everything worked very good for 1 year or so. I recently worked with a power tool that required a lot of power, a heat gun blower. It started to flicker when I use that blower. I originally thought are the leds, getting too hot and flicker from that. The lamp itself is getting hot usually. But now I thought this is it, too much hot for it and the leds are dying. If I leave the light off for a while, to cool down, it come in strong light as before. But after 1min or so of working, it start to flicker and fade to almost visible light. I figure out after a wile is my power supply. Today I change it with another one 5V 1.5A.
The old 5v PS had 1A and it was a power traveler - see picture:

I basically took out its board inside and reconnected everything to my needs. The white wires are the 220V wires. One of them is going to the switcher on the right, and one to the pile of wires in the left. I made a custom case for it, not to touch any metal inside.

I like this little board, because it fits very well inside that cramped space of my power tool.
Here you see it mounted back (and working fine now).

The new 5V board (no image), I took it from a transformer. But is a bit too big, and kind of fitted there to the limit. I liked the little one more because of it's space occupied.
I just look now, and the only voltage regulator that I have is LM317, but it works from a max of 37Vdc.
- My questions to you.
1- did my heat gun blower, created spikes that overwhelmed some components in my transformers? I notice a dim and very high pitched noise from another transformer on my table that is always on. It might be from that blower as well, or it is a coincidence.
2- Can you give me a circuit for a transformer, from 220V AC to 5V DC at 1A or 1.5A ? For the moment, the size doesn't matter. I want to see if I can make one and what components it takes. Also with good protection for mains spikes.
Thank you.

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#### LowQCab

Joined Nov 6, 2012
1,596
5V Transformer 3-Amps...........................DigiKey p/n.......595-1828-ND.................~$20.oo MOV.................................................................DigiKey p/n.......MOV-14D361K-ND......~$0.40
Bridge Rectifier 6-Amps, 1.6FV..............DigiKey p/n.......2796-GBU6B-T-ND.......~$0.32 Filter Capacitor 4700uf, 10V...................DigiKey p/n.......493-12442-ND................~$2.72
LDO Voltage Regulator 5V, 2A, .7V.....DigiKey p/n.......BA50DD0T-ND................~$3.oo Heat-Sink, 8-Watts @ 40C.....................DigiKey p/n.......533402B02552G-ND.....~$3.41
.
.......................................................................................................................................Total........~\$30.oo

This Power Supply is designed for 1.5-Amps, but may actually put out around 2-Amps.
Extremely smooth and stable.
A 6-Volt Transformer would be a better match if you can find one.
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#### djsfantasi

Joined Apr 11, 2010
8,065
Be careful using the term “transformer”. I think either you’re confused or are confusing forum members.

A transformer is a component. Like a resistor, cap, or transistor. You don’t need a circuit for it.

Additionally, a transformer may be used in a power supply to produce a different voltage from the input. In a power supply, you might use a circuit to produce the output. Besides the output voltage, you need to specify the allowed ripple, maximum current output, output stability, expected load…

Some of these may be “don’t care”, but that’s part of the specification. If you’re a noob, it’s understood that these may not be known, but a piece of advice that isn’t asked for… members with more experience will as these questions. Don’t get all snooty because you want a simple answer and believe there’s one. Members intent is to teach you and that’s why they ask questions that you believe are irrelevant.

#### q12x

Joined Sep 25, 2015
747
@LowQCab
Very good. In your example, you show a 5V transformer. But I do have left a couple of higher voltage (9V,12V) transformers around . I also have LM317 with which I can regulate to my desired 5V output and get up to 1.5A through it, though is not needed in this case. I thought of this possibility as well, but in this particular case, I need it to be slim as possible, so tranformerless is what im after. I will consider it as an alternative, if everything else fails ! This is plan B for me.

@djsfantasi
Thank you for the correction ! I am not an electronist, I do electronics as a hobby. In my mind, a transformer is a complex thing so I don't consider it a simple component, but it is mostly because im not working with them as often. So it is my ignorance. Im happy to be corrected, absolutely no problem there. I kind of knew it is considered a component, I read it before, but completely forget it when I was writing it down, concentrating to the context. I've also made another big mistake, and you catch that as well, not specifying correctly the term -power supply-, which is more closer of what I want. More specifically, I want a --transformerless power supply--, so without the transformer component. Now I'm glad I'm on the right track ! Haha. Like I mention, I want it to be as small as possible to fit in that small space inside my machine power drill. So I very much want to make it from electronic components , but except the transformer (because it will eat too much space alone). In conclusion, if you can share to me an interesting and simple circuit, it will be awesome.
Still, when I'm thinking "transformer" im thinking automatically on these relatively big ones, like a fist, 2inch height cube. But there are small ones, like 2 fingers, 1inch height cube. Again, im not working with them that often but I do know them to a degree. Also, there are tiny ones as well, especially seen in the smaller in dimention, PS (power supplies), the cheap ones. They are nail height cube and even smaller than that. I really have no idea how those are working. These tiny ones, are used exactly like the bigger ones? If you put one on 220V you get some 5V on the output? but at a very low current? Or they are there for completely other reason? I think they are not transforming anything, but more to balance some stuff. It is my impression, not knowledge. Please correct me on this part since im very curious what they are doing. I've also collected a whole bunch of them. I am willing to experiment with them if you will give me some proper directions.
Thank you !

#### Delta Prime

Joined Nov 15, 2019
1,213
More specifically, I want a --transformerless power supply--, so without the transformer component. Now I'm glad I'm on the right track ! Haha. Like I mention, I want it to be as small as possible to fit in that small space inside my machine power drill
Thank you, for stating your intent to miniaturize without using a transformer,(Your plan B.)On a previous post,I had to use my crystal ball in order to steer a fellow hobbyist, away from the AC mains. (Your house wall outlet. Direct connection no isolation.) Safety is number one!

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#### q12x

Joined Sep 25, 2015
747
The page you provided me, mister @Delta Prime is fantastic. Also a bit weird coincidence because it is from yesterday. I never known there are so tiny PSU's. I just looked straight away to the dimensions and is 33x22x15mm. Just WOW. Really fantastic !!! I love them. Though the prices... grrr.... that's why I wanted something to build myself. To have like 10 spares for a really cheap price. Safest way possible of course. Also from the reading, and I should remember this part in the future as well, you guys dont want to risk giving power advice , especially to unknown and possibly rookie characters as me here, as you put it: for liability reasons and also taboo( prohibited subject). Which is fair, from your perspective. Unfair for me, though. Just saying... and understanding your point.
In conclusion, my planB, ----> the transformer + voltage regulator LM317 is the safest way for you to advice and recommend.
Hmmm... I really need a very cheap way to power my led lamp bench.
I know an alternative though, the capacitive dropper. I tested successfully (some years ago) with maximum 5 power leds. My current leds from this lamp are a bit more bigger in dimension so I suppose they will ask more power, so I can guess (without testing) they will work 3 or 4 leds for a simple capacitive dropper.
This is my simple capacitive dropper test I build about 2 years ago, and its circuit I used.

I know for sure that I will need more power for this lamp and this alternative will not do its job.

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#### Delta Prime

Joined Nov 15, 2019
1,213
Hello, there again!
The page you provided me, mister @Delta Prime is fantastic. Also a bit weird coincidence because it is from yesterday. I never known there are so tiny PSU's. I just looked straight away to the dimensions and is 33x22x15mm. Just WOW. Really fantastic !!! I love them
You have just experienced Biodirectional Causation! Initiated by standing on the shoulders of giants.(This Community)

#### q12x

Joined Sep 25, 2015
747
Other ideas please? I want more alternatives. Or this is it, this is all.

#### q12x

Joined Sep 25, 2015
747
Ok then, can anyone tell me what is the principle of a low power switch mode power supply?
For example 5V-1A-5W.
Here is just a visual reference of the low power supply I'm referring to:

#### q12x

Joined Sep 25, 2015
747
Hmmm... I found myself a couple of youtube principle very good explanations of a SMPS.
It is a complicated subject !!!
Very interesting and practical subject. It is a shame you are afraid discussing it !!!

#### Delta Prime

Joined Nov 15, 2019
1,213
Very interesting and practical subject. It is a shame you are afraid discussing it !!
It was Friday night!! I was caught up in a Quantum Entanglement.
It's what I do...
Besides, new subject, new thread, start a new one.
And if you do... Practice your best behavior! Or I'm going to call up this guy, to confuse you to death!!