Quiz Question

One of a continuing series


When I was out in California a few years back there was this public service ad that kept popping up on cable TV. It featured three teens having a conversation. One little girl was being chided by her friends for leaving her phone charger plugged in when she wasn’t actually charging her phone. That sounded cool. Don’t waste electricity needlessly. Of course, not much goes into powering a smart phone charger, so it’s not like leaving the A/C turned on when you go on vacation.

Then it occurred to me that phone chargers don’t draw power when they aren’t charging the phone. And that’s this week’s Quiz Question. What’s a quick and painless way to verify your phone charger is not drawing power when it’s not charging?

Post your answer in the comments section.

Update and answer

Mike has the right idea (see the comments), but it is not as hard as he makes out. Just put your hand on your phone charger. If it’s warm, it’s dissipating (and wasting) power. You don’t need a sensitive thermometer. With most devices I’m thinking you can feel the temperature rise due to one Watt, or less.

4 thoughts on “Quiz Question

  1. Maybe if you had a really sensitive thermometer, you could decide that it was not getting any warmer than ambient.

  2. Pingback: Quiz Question | Skeptical Analysis

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