In the last post I complained about searching for basic electrical information, such as wire color coding, in the middle of an electrical project.
This happens all the time. As the years and projects pass, I retain more and more electrical information from one task to the next. But, as I face each new job, my stress level increases to the point that I’m more likely to forget what little I do know, and less likely to reason out what I don’t. In the heat of battle, as it were, I often can’t keep enough composure to remember the simplest things.
A classic example: my voltmeter is set up to measure AC and DC loads. I turn a dial to the type of current I need to measure. But, they’re not marked “AC” and “DC,” they’re marked “V” for volts, then a symbol— “~” (tilde) for AC, and a solid line with a dashed line underneath it for DC.
In calmer moments, I can tell you that the ~ stands for AC. Alternating current oscillates, making a sine wave, which the tilde represents graphically.
More critically, which wire do you disconnect from the battery first, negative or positive? Continue reading
