Static vs Current Electricity
Static electricity is charge that builds up in one place — like when you shuffle across a carpet and get a shock. Current electricity is charge that flows steadily through a conductor, like in your home wiring. Both involve electrons, but current electricity has them moving.
Voltage: The Push
Voltage (measured in volts) is the 'push' that moves charge through a circuit. Think of it like water pressure in a pipe — high pressure pushes more water through. A 9V battery pushes harder than a 1.5V AA battery.
Current: The Flow
Current (measured in amps) is how much charge flows per second. 1 amp = 1 coulomb per second. A tiny LED might use 20 milliamps. A microwave might draw 10 amps. Current is what actually flows — but it's the voltage that pushes it.
Resistance: The Obstacle
Resistance (measured in ohms) is how much a material fights the flow. Copper wire has very low resistance — great for carrying current. A lightbulb filament has high resistance — it glows because the resistance makes it hot.
Ohm's Law
V = I × R. Voltage = Current × Resistance. This triangle is the most important equation in basic electricity. If you know any two, you can find the third. Every circuit design starts here.