# How to identify the correct power supply for a device [duplicate]

I imported a lamp from China to the UK, which came with a power supply terminated with a Chinese 2-pin plug. I'd like to use a UK-made power supply, but am not sure what I need to purchase.

I have been browsing for "12V 1A" power supplies on eBay/Amazon, and some mention a Wattage (e.g. 12W). Is this also a factor I need to consider?

The base of the smart lamp mentions "9W":

I can see "0.5A" mentioned on the Chinese power supply, which is obviously not the same as the "1A" written below it, so presumably refers to another variable that I need to consider.

not my pictureAlternatively, I could source a "travel adapter" and use the original power supply through a China to UK plug adapter, however I do not know how safe this is for long term use. I have read many scare stories online about "Chinese" plugs being unsafe and a fire hazard, but without much information as to what makes them "unsafe" so what to look for in a "safe" plug!

(not my picture)

You have to find a power supply that gives 12 V, also make sure the pins that connect to the plug (not in the socket but in the device) has the + and - correctly (some barrel plugs have the + as the inside pin, and the - on the outside, or vice versa). Looking at the picture your supply expects the + on the inside pin.

The power, should be AT least the one that is mentioned on the Chinese supply, which is 1A. It does not matter if it can handle more current/power, but it is a problem if it can deliver less. The 0.5A is the output of the wall outlet (which seems really high, but does not matter in this case). It would mean that your 100-240V socket takes 0.5A which means 100 V * 0.5 A = 50 W which is much more than the output of 12 V * 1 A = 12 W... so either the 0.5 A is slightly a too high value, or the supply is really inefficient (could be both).

The lamp will require current, if the supply cannot deliver it, it either overheats, stops working or some safety measurement will apply. In case of a Chinese power supply, it might overheat, which can result in fire.

So to summarize, find a power supply that:

• Has 12 V
• Has at least 1 A
• Has the + of the barrel on the inside pin
• In the EU power supplies and chargers that have been officially imported for sale must fulfill certain requirements about fire and electrical safety. For example the plastic case must be such that it does not continue burning but extinquishes the flames, and the electrical isolation between mains side and low voltage side must have a certain level of safety and fault tolerance so that low voltage side does not become live with mains to prevent electrocution. Cheap/foreign devices may not be up to local standards. And while you are allowed to buy stuff from abroad, you choose the risk. – Justme Nov 1 '19 at 13:07
• @Justme Thanks for this useful addition regarding safety. – Michel Keijzers Nov 1 '19 at 13:28
• @Justme You are allowed to import to the EU, for the moment. Regulations are due to be significantly tightened shortly including seizure and destruction of individual distance-sold products. See 2019/1020 for the gory details. – Spehro Pefhany Nov 1 '19 at 13:34