Ok so this section is called Current, but its really just about measuring current with your multimeter, the safety concerns inherent to measuring current, and me making very sure that no one following along at home drains their battery or fries their multimeter.

But before we get into that, let's review everything you should know about current:

Current is how many electrons are flowing past a point in a circuit.

The electrons flow from the negative end of your battery, to the positive end.

Current is measured in amperes - abbreviated as the capital letter A, and usually shortened to “amps”.

If you’re building small audio and light circuits, as we are, the current in your circuits will typically be measured in milliamps (mA), which is thousandths of an amp. So one milliamp is 0.001 amps.

One amp of current means there is 6,250,000,000,000,000,000 electrons flowing past that point per second. That seems like a really arbitrary number, and it kind of is, but there’s a good and excessively long reason for why it is what it is, which we’ll hold off on for now.

Now that all that's out of the way, here is how you measure current.

Note: There is lots of useful information in the video demos below, and you should totally watch them. But after some recent user testing, I am going to suggest that you do NOT yet measure current with your multimeter, because it is amazingly, almost comically easy to damage the meter if you make a mistake. You'll see more on why in the next section, on fuses.