Every electronic circuit has some noise and it can affect both analog and digital circuits. Some noise comes from outside interference while some comes from random factors such as thermal effects.

The RMS value of a time dependent voltage or current is based on the simple concept of equality of power dissipation; however, its theoretical calculation or instrument implementation may not be easy.

How many times have you poked around a circuit with a digital multimeter (DMM), read an AC voltage value, then gone on your merry way? Ever wonder if your meter is giving you peak value, average value ...

The first time I was in school for electrical engineering (long story), I had a professor who had never worked in the industry. I was in her class and the topic of the day was measuring AC waveforms.