220V ChineseTransformer

Thread Starter

Khisraw

Joined Nov 14, 2020
56
Hi,
I am looking for a 220V transformer and I see a few on the RS or Mouser which are expensive. But on AliBaba, I find it as cheap as $0.5.

https://www.alibaba.com/product-det...rlist.normal_offer.d_title.1dc95a8cn018Ag&s=p

It seems these transformers are now on many boards like SonOff and ESP8266. But I cant find the manufacturer or datasheet for it.

Does anyone have experience using them on an actual product, not just prototype or Ref design boards? I am curious to know if I can trust it in the long run?
As they say cheap is always more expensive :)
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LesJones

Joined Jan 8, 2017
4,174
The transformers in your link are high frequency transformers (tens of hundred of Khz.) used in switch mode power supplies. Is that what you require ? Or do you need one to work at mains frequencies (50 / 60 hz) ?

Les.
 

Thread Starter

Khisraw

Joined Nov 14, 2020
56
The transformers in your link are high frequency transformers (tens of hundred of Khz.) used in switch mode power supplies. Is that what you require ? Or do you need one to work at mains frequencies (50 / 60 hz) ?

Les.
I need one for mains frequency
 

DickCappels

Joined Aug 21, 2008
10,153
The nice thing about a good genuine USB charger from a reputable company that they have been through safety engineering and testing. There is more to an approved power supply than what you can see.
 

DickCappels

Joined Aug 21, 2008
10,153
Since the manufacturer is not mentioned and no safety marks are visible I would be worried about this one.

You can buy and experiment with stuff like this but you must be very careful when doing so.
 

Audioguru again

Joined Oct 21, 2019
6,672
To promote electricity power reduction, my electricity utility company gave away free compact fluorescent light bulbs.
BUT some of them caught on fire and dripped flaming plastic. They were all recalled and replaced.
They discovered that the cheap Chinese manufacturer illegally copied the certification label of a competitor so these light bulbs were never certified to be safe.
Buy cheap then get cheap.
 

Thread Starter

Khisraw

Joined Nov 14, 2020
56
To promote electricity power reduction, my electricity utility company gave away free compact fluorescent light bulbs.
BUT some of them caught on fire and dripped flaming plastic. They were all recalled and replaced.
They discovered that the cheap Chinese manufacturer illegally copied the certification label of a competitor so these light bulbs were never certified to be safe.
Buy cheap then get cheap.
Can you name these compact fluorescent light bulbs?
 

Reloadron

Joined Jan 15, 2015
7,501
When it comes to transformers names like Hammond, Stancore and a few others come to mind. Buy once and cry once. If all I want is low current DC at 5 volts I would just buy a simple and inexpensive wall wart from Amazon. Most will work fine on 100 to 240 VAC 50/60 Hz input and output as much as 2,000 mA (2.0 Amp). Most are under $6.00 USD in cost. While of Chinese make this is the inexpensive approach over a roll your own power supply including regulation. Around my area the second hand stores have buckets of them for a buck or less.

As to CFL bulbs? While I can't name a manufacturer of defective bulbs I would suggest when buying a bulb only buy a reputable name brand. While just about all of this stuff is Chinese manufacture the reputable name brands should be made to specifications. Also buy from a reputable source to avoid counterfeit junk falsely labeled.

Ron
 

kirkmans

Joined Mar 13, 2011
4
Buy something with UL and FCC approval. Otherwise it could cause radio interference, be dangerous or fail early in life. I had one cheap one where the secondary was not isolated from the primary. Got shocked touching ground. Never again.
 

sparky 1

Joined Nov 3, 2018
756
The picture of the yellow transformer is helpful. Probably a step down converter transformer.
Any way of safely testing to find the primary to secondary ratio ?

A Chinese description might read like this:
Universal mains input. "AC input 85V to 265V AC"
maybe one of those ?
 
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