Technician License Course Lesson 3.1

Here’s your video introduction to Lesson 3.1 in the ARRL Ham Radio License Manual. Mea culpa: a verbal typo – I say that voltage flows from positive to negative. It’s current that does that, of course!

Hold the fort! I got a comment on YouTube “from Skylane Captain”:

Could you clarify the multiplication at 2:55 please……120 volts x .210 amps = 25.2 not 13. Thanks.

Here’s what I wrote in reply:

Thanks for the good catch. Indeed your math is correct. I should have caught that. The 13 watts comes from the fact that 0.21 amps is peak, not average (the bulb is not drawing a constant amount of power all the time). I don’t have an o-scope, so can’t check, but I suspect that it draws power only on the half cycle. If you have an o-scope, that would be an interesting thing to check out. It’s also possible that it draws 0.21 amps when starting, but settles back to a much lower amount – they have to list the maximum amperes it draws.

To return to the lessons page, click here.

This entry was posted in Ham Radio blog entries, Technician Class License Training. Bookmark the permalink.

1 Response to Technician License Course Lesson 3.1

  1. Gordy says:

    I stumbled across you while looking for a class. I now have orders the book and am really exited to get going. Your first video really relieved a lot fears. Thank you for taking the time.

Comments are closed.