At AutoEDU, we believe the best way to learn about electricity isn’t just by reading about it—it’s by seeing it, testing it, and experiencing it. That’s why our training programs are designed to help students connect classroom theory to real-world automotive systems using practical demonstrations and easy-to-understand explanations.
Electric current is the movement of electrons through a conductor. It’s measured in amperes (A). One ampere means approximately 6.24 × 10¹⁸ electrons pass a single point in a circuit every second. This quantity of charge is called a coulomb, named after the French physicist Charles-Augustin de Coulomb.
While we can’t see electrons with the naked eye, their effects are very noticeable. We feel heat from wires, see light from bulbs, and observe electromagnetic forces in motors. Tools like digital volt-ohm meters (DVOMs) and oscilloscopes allow us to measure and analyze these movements precisely.
Voltage is the potential force that drives electrons to move, and it’s measured in volts (V), named after Alessandro Volta. Imagine stretching a rubber band. The more you stretch it, the more potential energy it stores. When you let go, the energy is released.
A battery works in a similar way. Electrons are pushed away from one battery plate and gathered on another, creating an imbalance. This imbalance builds up electrical pressure—voltage. The plate with more electrons becomes the negative terminal, and the plate that has lost electrons becomes the positive terminal. When the two terminals are connected through a conductor, the electrons naturally flow back to their original position. This is called direct current (DC), where electrons flow in one direction.
As electrons flow, they don’t move freely without opposition. This opposition is called electrical resistance, measured in ohms, and named after Georg Simon Ohm. Resistance depends on several factors: the type of material, its temperature, length, and cross-sectional size.
Materials like copper, silver, and aluminum allow electrons to pass easily and are known as conductors. Insulators like rubber or plastic have tightly bound electrons that resist flow. However, if the voltage is high enough—as in the case of lightning—it can overcome even the resistance of air.
To demonstrate electricity in a simple and memorable way, we use an experiment with everyday items. Students insert a brass screw and a galvanized screw into a lemon or potato, then use a DVOM to measure the voltage. This basic setup produces around 600 to 1,000 millivolts. Connecting an LED allows students to see the electrons flowing and lighting the diode.
By switching the DVOM leads, students can identify the polarity of each screw and see which one becomes the negative terminal. If multiple lemon or potato batteries are connected in series—positive to negative—the total voltage increases. This fun, visual activity helps students understand voltage, polarity, chemical reactions, and electron flow.
Just like stretching and releasing a rubber band, a battery can be charged and discharged. When electrons return to their original positions, the battery is considered discharged or “dead.” Charging the battery pushes electrons back to their previous plates, building voltage again. However, just like a rubber band weakens after repeated use, batteries degrade with time and usage.
Power is the rate at which electrical work is done. It’s calculated using the formula:
Power (Watts) = Voltage (Volts) × Current (Amps).
Power ratings are critical in automotive systems. A device’s ability to function without overheating depends on matching its power rating to the current and voltage it receives. For example, if students connect three resistors with the same resistance but different power ratings, they’ll see that the lowest-rated one may burn out, while the highest-rated one remains cool—even under the same electrical load. This helps them grasp how power affects performance and safety in real systems like starter motors, alternators, and audio equipment.
By the end of these lessons, students understand much more than just theory. They can explain how electricity works, where electrons come from, and why a battery charges or dies. They know how to use Ohm’s Law to calculate current, voltage, resistance, and power, and they recognize how these principles apply to the vehicles and devices they’ll work with in the future.
At AutoEDU, we make sure students don’t just memorize—they experience. Our hands-on training connects the dots between textbooks and real-world diagnostics, setting the stage for confident, competent automotive technicians.
