It seems that it would be more sensible to have a charger that can accept the full range of input voltage, however if this isn't possible, then you're going to need a way to get the voltage down to something you can measure. A 100:1 transformer, rectifier, and capacitor, would give you a low DC voltage you can measure and compare. A microcontroller is likely the simplest way to do the measurement.
Posts by catphish
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I agree that trying to dynamically switch this without a carefully designed bespoke solution would be extremely dangerous, as a 240V input could easily be detected as 120V for a brief period during plug-in. In my opinion you need to sample the voltage for at least 1 second before making a decision which circuit to enable. I wouldn't dream of doing anything but buying a new charger with a wide voltage input though.
This would definitely work if it defaulted to the 240V option and had a reasonable settling time.
I wouldn't quite trust it, but it would work.1 - 3 of 25 Posts
