When looking on-online, I see several 115V AC to 5V DC step-down or Buck converter. I wonder which one should I get, from the ever so popular Hi-Link to A random 5 Volt AC/DC converters. I mean, after viewing the datasheet for the Hi-Link. They recommend adding a couple capacitors, Coil, and more Electronic components. If you have to add more components why don't you just go with A random AC/DC Type Transformer. Efficiency, Current and price are major factor and or course. Are there other factors in play here?
You can find working, well made "wall wart" 5V phone chargers, monitor and game power bricks offering various voltages, by the dozens, for next to no cost, in thrift shops, computer recycling shops, etc.
Make sure it can supply the current your project requires.
A Buck converter is DC to DC, I have often used them for 12VDC input and 5VDC output. If I need a AC to DC power supply like a phone charger, I use one of a dozen spare chargers I already have for many devices. These will have a variety of output possibilities from 5VDC to 12VDC.
jremington- Hmm.. Unfortunately, I don't have any extra phone charger or any extra AC/DC power adaptors as that was my first thought, of course. Nor, would I purchase one for my small hobby enthusiast. As the local phone charger are overprices here in the US.
So, let me ask again..Hopefully I can get a direct answer and not a secondary suggestion.
Is there a good Step down Mods or are they all Mostly the same?
yes, there is another unimportant and overrated factor, that I suppose that you already know. That thing can kill you, and can also kill others.
It's ok to build or use these kind of circuits, I suppose that you know what you do, but it is something to take into account. Also the final destination of the device, isolation, etc.
I am not sure what you call expensive, but in Canada where the prices are 30% MORE, I can get at least 2 chargers for $13CDN, probably less than $10USD. Here is one link (change country to make local; purchase) https://amz.run/9SAK
Yeah, Canada is expensive but then the pay/hour is more. It's all subjective. I did find some USB phone chargers for 3.50/1 Amp each but, Those don't work for PCB mount. Anyways, I'm going with A AliExpress 5V/700MA step down Transformer. As .7Amp is all I need. Plus, it's extremely small, PCB mountable and only $1.17US with shipping.
People, don't be stupid cheap about these small mains SMPS boards.
There are safety issues regarding fire and electrocution that you don't get for $1.00 lol.
First, always look for a fuse. There should be an input choke for filtering RFI as well as an output choke for filtering RFI and not polluting power to your wireless modules, giving you poor even terrible range. It should use a TL431 and opto-coupler for good regulation.
I could go on, but you don't want it to burn the house down or electrocute someone.
These work fine for me: https://www.aliexpress.com/item/1005006216979532.html although the capacitors get hot at 2A, I would rate it 1A.
The cheap 5V 700mA board WX-DC12003 has none of this, it's dangerous and the PC board spacings are terrible. Not recommended at all.
Or, just buy a name brand like from Ikea it has all the safety certificates as well.
Your funny.. How can it kill you? Certainly you can't be referring to the 120/60Hz AC US Current. After all nobody has died touching a 120 Volt outlet in the US. Sure, if your touching the mains house power. Maybe, you feel the need to over dramatic or it's a liability issue for public forums. I truly have always wondered.
If you have to add more components why don't you just go with A random AC/DC Type Transformer
For me the the most crucial requirement is safety. If you google something like "wall wart teardown" you will see that a number of wall warts (phone chargers) coming from China do not meet even the loosest of specification with regard to safety. I cannot imagine the open boards you referenced are any different.
I mean really, what type of design would you expect for $1?
Every power supply where input to output isolation is required (for safety) has one component that must provide the isolation you need to be safe, that is the switching transformer. Many of the cheap supplies have little or no insulation between the primary (connected to the mains) and the secondary (connected to the parts you are touching).
Are you serious?! It's not the voltage that kills, it's the amperage.
Don't earn a Darwin Award like poor Javier here:
In a bid to enhance his fishing prowess, Javier Hernandez from Mexico improvised a fishing rod with a live electrical wire, intending to stun fish in nearby waters. However, his lack of understanding of electrical currents and aquatic environments proved fatal. The electrified fishing rod became a conduit for his demise, highlighting the dangers of combining electricity and water. Best & Funniest Electrical Darwin Awards
It sounds like you've already made your decision. However for my parting statement....
If the high voltage transformer in one of these devices fails by shorting between the primary and secondary, they you will be touching mains voltage if you touch anything connected to the output of the AC/DC converter.
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