Electricity: Voltage, Current & Resistance
The water analogy that makes circuits click
The water analogy that makes circuits click
Electricity is invisible, but water is not. Voltage is like water pressure. Current is like flow rate. Resistance is like a narrow pipe. Adjust the sliders to see how they relate.
The most important equation in electronics. Adjust any two values and the third is calculated automatically. The triangle shows the relationship.
Power is voltage times current. It measures how much energy the circuit uses per second. Your phone charger, light bulbs, and appliances are all rated in watts.
5V * 1A = 5 watts. Enough to slowly charge a phone.
As bright as a 60W incandescent. LEDs are 6x more efficient at converting electricity to light.
1000 watts = 1 kilowatt. Enough to boil water in minutes.
A bolt of lightning carries about 1 billion volts and 30,000 amps for a few microseconds. That is 30 trillion watts, enough to power a city for a few seconds, if we could capture it.
You now understand the three fundamental quantities of electricity: voltage pushes, current flows, resistance opposes. Ohm's law ties them together. Every circuit from a flashlight to a supercomputer obeys these rules.
Voltage is electrical pressure. Like water pressure in a pipe, it pushes electrons through the wire. Higher voltage = more push. Measured in volts (V).
Current is how many electrons pass a point per second. Like the flow rate of water. More current = more electrons moving. Measured in amps (A).
Resistance slows current down. Like a narrow pipe restricts water flow. Higher resistance = less current for the same voltage. Measured in ohms.
Voltage equals current times resistance. Know any two, calculate the third. This single equation is the foundation of all circuit analysis.
Put your new knowledge into practice!