# Why are electric blankets AC? [closed]

You’d think electric blankets would use a 12V DC adapter to step down the 240V AC to 12V DC. It has the potential to be just as effective while also being safer. Do you think it’s because of the additional cost of the wall adapter?

• A heater doesn't care if it's AC or DC and DC doesn't mean safer. DC just means more work in this case. Safety is in the magnitude of the voltage and whether it's isolated or not. What do electric blankets use? Commented Feb 24, 2020 at 2:46
• DKNguyen is it not true that at a DC signal at an equivalent magnitude to an AC signal is just as safe but also provides more power? Therefore you’d need to increase the AC voltage magnitude to deliver the same quantity of power as that specific DC signal, thus making it less safe than the DC signal? Commented Feb 24, 2020 at 3:21
• Your phrasing is ambiguous and could be more specific with regards to ratings. RMS voltages, whether AC or DC, will provide the same resistive power. But the peak voltages for the RMS AC will be higher than the RMS DC. But then let me ask you this: If you're going to step it down why go to the trouble of stepping it down to 12VDC when you could just step it down to 12VAC? Is 12Vpeak from 12VDC really any safer than 17Vpeak from 12VAC? Is 120VACrms (170Vpeak) really any safer than 120VDCrms (120Vpeak)? Commented Feb 24, 2020 at 3:32