Troubleshooting Techniques: Making the invisible visible | Tech, No Babel

Transcript: As we’re troubleshooting, you’ll notice that despite what you see on movies, electricity is, most of the time, invisible. Sure, there can be an occasional spark. Lightning you can see, but when you’re dealing with low DC voltages or even just regular household current, if you can see it, something has gone dramatically wrong.
How can you tell what’s going on? First off, you can look for lights or anything in the user interface to help you, but there are a couple of other features. First off, when it comes to remote controls, this is a remote control that I have here in the office. You’ll notice something about it. If you’re looking at the video and you look on the end, there’s no LED on the end. That’s because this is an RF remote. This is an unusual type of remote. You won’t find these very often. Seeing if this is sending a signal, basically I can just press the LED and see if it lights up. You might have actually heard some clicking behind me because that goes to a piece that controls the volume in the setup. That’s really all you can do, but happily, most remote controls are not like that. Most remote controls are like this one. This is the one to my television. You’ll see a little LED on the front. Sometimes that’s covered over with a plastic that’s translucent, but it’s there nonetheless.
Wouldn’t it be great if when you pressed a button you could actually see light coming out of there? Right now I could press the button all I want and I could look at it and I won’t see any light. Let me give you a quick trick. This is being recorded on a camera, a DSLR in this case. Cellphone cameras tend to do this too. It is possible that it would be filtered out, but typically it’s not. That’s this. I’m going to shine this directly at the lens and press the button. Can you see that? It’s blinking. But when I look at it in person, I can’t see it.
That’s because while cameras have a smaller dynamic range, they see things that are dark as darker than they are to our eyes, and things that are bright as brighter than they are to our eyes, they also reproduce more of the spectrum than our eyes can. They see infrared light as a blinking white light. You can use a regular video camera or your cellphone camera even to tell if the batteries are actually good in the remote.
Now that’s just one of the tricks that you pick up over the years of making invisible things visible. There are also cables that are manufactured that will light up when they have power going through. That’s a way to make the invisible, the 12 volts or the 5 volts or what have you, visible so that you can see if it’s doing what it’s supposed to be doing.
That might be worth doing, is having some of these cables on hand that if you have a problem you can temporarily replace them for troubleshooting purposes to see am I getting power through that. Another great way of making the invisible visible is the use of a multimeter. A multimeter is a piece of test gear that enables you to test and see numbers for voltages, see numbers for amperages, etc., see if there’s continuity. That way you can tell if electricity is flowing. Using a multimeter is a little bit more complex, so I’m going to save that until next time.