5 ms·
I don't really understand how there's 120V at the tip when it's plugged into the Apple USB powers supply. Isn't there a gap between the AC and DC electronics?
by voltagex_ 11y ago
I don't really understand how there's 120V at the tip when it's plugged into the Apple USB powers supply. Isn't there a gap between the AC and DC electronics?
- foldr 11y agoIt's normal for these sorts of power supplies to have a small leakage current. Hopefully someone else will be able to explain the details, but as I understand it it's the result of capacitative coupling across the transformer and filter capacitors.
- cellularmitosis 11y agoI can't explain the details, but I was able to measure the current. Interesting that I didn't measure any current from a genuine Apple charger, but enough current to cause a tingle from the cheap import chargers. https://www.youtube.com/watch?v=pjz4I69YoUA https://www.youtube.com/watch?v=pjz4I69YoUA
- c22 11y ago> but enough current to cause a tingle from the cheap import chargers. You should try using a multimeter!
- cellularmitosis 11y agoUm, I did, as shown in the video...
- deleted 11y ago[deleted]
- brian-armstrong 11y agoThe voltage is mains AC, but the current is measured in microamps. It's still enough charge to cause static discharge.