Where do spark plugs get their electricity?

Question

Where is the electric charge coming from and does it have a large amount of electric charge to it?

Answer 1

From a device called a coil. The coil is basically a transformer which takes in the 12vdc voltage from the battery and upconverts it to around 40k vdc (depending on the ignition system). Here is a breakdown of what a basic coil looks like from the inside:

The battery input feeds the primary coil. This is a thicker wire with a number of windings. The secondary coil is where the magic happens. There are a larger quantity of windings within it. Basic electrical theory shows us as we transfer power from the fewer windings of the primary coil and the secondary coil picks it up with the huge number of thinner windings, this will increase the voltage of the electricity. While this increases the voltage, the amperage is decreased at the same time. You can read more about how it works in this How Stuff Works article.