3 ms·

This is rather easy to tell. Leave your charger unplugged for an hour and feel how cold the plastic gets, then plug it in to let it idle. If you have a switchin

This is rather easy to tell. Leave your charger unplugged for an hour and feel how cold the plastic gets, then plug it in to let it idle. If you have a switching charger it should stay around roughly the same temperature as when it was unplugged, if it feels like it gets warmer then that means it's in idle and not switched off. The flat-form transformers used in most cell chargers are rather inefficient, so the temperature difference tends to be more than expected. However when you're dealing with ~9W maximum, it's likely more energy efficient to produce a less efficient transformer than consume extra time on the production line.

mseebach 17y ago
Yeah -- and there also size (very small), weight (very light) and sound (coils hum at 50/60 hz, the switching ones "whine"). But I wouldn't think the lack of heat that I can feel means that it doesn't waste 2.3w?
- moe 17y ago
  If by "whine" you refer to a very high pitched noise (akin to a TV tube) then I'll take a non-switched one every day. I have two such mosquito-infested powerbricks here, emitting a constant high-pitched noise each, and it's royally annoying. The charger for my DECT phone emits it when the handset is not sitting on it and one of my two BenQ screens (ironically both the exact same model!) emits it when turned off. This may be an avoidable production bug but when it strikes it's plain out horrible. I had to ban that DECT-charger from the living room because the sound would drive us nuts... (And yes I should have returned both items as defective but on the phone I was too lazy and on the screen the noise only started after it was about 2 yrs old)
  - mseebach 17y ago
    It is, and I've had some of the bad chargers as well. Usually, however, I have to press my ear against the brick to hear it at all, and have really good hearing.

mseebach 17y ago

Yeah -- and there also size (very small), weight (very light) and sound (coils hum at 50/60 hz, the switching ones "whine"). But I wouldn't think the lack of heat that I can feel means that it doesn't waste 2.3w?

moe 17y ago
If by "whine" you refer to a very high pitched noise (akin to a TV tube) then I'll take a non-switched one every day. I have two such mosquito-infested powerbricks here, emitting a constant high-pitched noise each, and it's royally annoying. The charger for my DECT phone emits it when the handset is not sitting on it and one of my two BenQ screens (ironically both the exact same model!) emits it when turned off. This may be an avoidable production bug but when it strikes it's plain out horrible. I had to ban that DECT-charger from the living room because the sound would drive us nuts... (And yes I should have returned both items as defective but on the phone I was too lazy and on the screen the noise only started after it was about 2 yrs old)
- mseebach 17y ago
  It is, and I've had some of the bad chargers as well. Usually, however, I have to press my ear against the brick to hear it at all, and have really good hearing.