Just got a new power quality meter and it's more fun than OK Go "This Too Shall Pass." We used it for the first time in the entertainment electricity, power distribution, and controls class at Texas State University this week. First we connected it to a conventional fixture and saw the voltage and current wave form. Then we connected it to an LED fixture and saw the harmonic content added by the pulse-width modulation power supply. But when we connected it to an audio amplifier the harmonic content shot up to about 33%. The more we move towards switched-mode power supplies, LEDs, projection, and other non-linear loads the more power quality becomes an issue. In the early '80s when PCs became popular and everyone started plugging them in, feeder transformers were having a hard time because the 3rd order harmonics were causing large currents to flow in the neutral. So they started manufacturing K-rated transformers. Now we're increasing the number of non-linear loads in shows without really paying much attention to our neutrals. I'm very curious to meter some very large shows and see just how serious this problem is. Now that I have this meter I'm on the hunt.