The Foundation of Electronics
Ohm's Law, named after German physicist Georg Simon Ohm, is the most fundamental relationship in electrical engineering. It describes how voltage, current, and resistance interact in a linear circuit.
- Voltage ($V$): The electrical pressure or "push" provided by a power source.
- Current ($I$): The actual flow of electrons through the circuit.
- Resistance ($R$): The opposition to that flow.
The "Water Pipe" Analogy
To visualize Ohm's Law, imagine water flowing through a pipe:
- Voltage is the water pressure.
- Current is the volume of water flowing through the pipe.
- Resistance is the narrowness of the pipe.
If you increase the pressure (Voltage) while the pipe width stays the same, the water flow (Current) increases. If you keep the pressure the same but make the pipe narrower (increase Resistance), the flow (Current) decreases.
The Formula
Where:
V=
Voltage (Volts)I=
Current (Amperes)R=
Resistance (Ohms)Example Calculation
You have a $12 , \text{V}$ car battery connected to a lightbulb with a resistance of $6 , \Omega$.
- Use Current Formula ($I = V / R$): $12 / 6 = 2 , \text{Amperes}$.
The bulb draws $2 , \text{A}$ of current.