| Electronics > Beginners |
| Conversion Formula |
| (1/1) |
| Bill8989:
Hi, I was wondering if anyone could tell me how I could work out the energy losses from the AC-DC step down when I plug my 5v phone charger into a 230v RMS AC mains supply? given that my phone is probably drawing around 1A and this should give a 5W load on the supply. |
| ArthurDent:
Most chargers are switching mode power supplies (SMPS) and have a conversion efficiency of 80%-90% plus as your phone approaches full charge, the current it draws will drop quite low. I would guess that the load on the mains initially would be a maximum of about 6 watts and drop to a very low value as the phone is charged. I use a Kill-A-Watt monitor which is fairly cheap and could gives me information on the mains side. Just make sure to get the UK version. https://www.amazon.co.uk/Energenie-429-856UK-Power-Meter/dp/B003ELLGDC |
| Navigation |
| Message Index |