My dad might just be the most difficult person I know to find gifts for. Unlike other dads, who might enjoy fishing, golfing, or watching football, mine rides and restores vintage motorcycles for fun. What’s so difficult about that? Well, there are only so many spark plugs and screwdrivers he needs, and only so many specialty parts I can track down before I’m in over my head.

That’s why I went out on a limb this Christmas, and decided to give him one of our

As you can see, the light’s long neck lets it curve and reach to illuminate the motorcycle’s body for detailed work.

Electricity exists everywhere, from high voltage power lines to phones and computers. Understanding the basics of how it works remains essential to using it safely and efficiently.

When electricity travels from a positive lead to a negative lead in a circuit powered by a battery, it is considered direct current. This type of current powers electronics, LED lights, and cars. Alternating current is generated from rotation, usually by a generator. The direction of the current and the voltage flips as the generator completes a rotation. The faster the generator spins, the faster the flipping of current direction occurs. In North America, the typical frequency of AC power is 60hz or 60 alternations per second. The advantage of AC power is that the voltage can be stepped up easily by use of a transformer, which allows high voltage transmission. AC power is also useful for electric motors.

Specifically, power is a measure of energy usage over time. The standard unit of power is the watt and calculated as P (watts) = V (volts) x I (amps). Utility companies sell electricity in units of kW*h (kilowatt hours), which is simply one kilowatt of power delivered continuously over one hour.