Meters for Diagnosing Electronic Circuits

Video Transcript

"This is Larin Parker for Expert Village! I'm talking about the more specialized tools that we have to diagnose our audio equipment. Number one would be the multimeter, which I strongly recommend that everybody have if their doing any bit of electronics work at all. Except for the very, very basics. What it does is this one measures, almost all of them usually measure voltage, resistance and current. Probably the two most important measurements the ones I do the most are: voltage and resistance. Then another nice feature is they have a mode usually indicated by this little musical note where if you touch the two leads together, on this one my speaker has gone out but if you touch the two leads together it will read a zero and then if my speaker were going it would go beep. That lets me know that a circuit has continuity. For measuring resistance I just turn the dial to the highest resistance that I think I'm going to see. If I think it's going to be between zero and twenty k I turn it to twenty k and then I measure something, and I 'm just touching the these guys together, so of course I'm measuring zero. Then if it were to measure something higher than twenty k, it would tell me to go higher and then I would set it up to something like twenty mega ohms and then measure at that point. So essentially we're just setting the precision. We can go down to zero to two hundred within a tenth of an ohm and then we can go all the way up to two hundred mega ohms. That's actually measuring some resistance you can see the amount of resistance in my skin is two mega ohms right now between these two leads. So it can measure quite a bit of resistance. The other one would be voltage and here?s DC voltage which is what we deal with the most. Once again you choose the setting that is higher than the value that you expect. Two twenty, two hundred, one hundred. If I were looking at something that is suppose to be about twenty volts, I'd set it to two hundred, if I were looking for something that?s about ten, I'd set it to twenty because that?s the next number up. Then of course, one of my favorite tools is portable speaker, battery powered speakers are often better than using wall plug speakers because you can take them with you. Also there?s no chance that any problems could cross over the cable and enter into this battery powered speaker, and if it did it's just a battery powered speaker that I can replace easily. Then of course if you get more advanced we have the oscilloscope, this is a portable model which shows you the wave forms that are present at its tip and you can actually see the audio waves if you hook it up to a circuit board inside the equipment. These are a little trickier to use but you can find a lot of information out about them on the web. Those are the tools that I use the most probably the speaker and the multimeter are the most useful, checking voltages and just listening for sounds."