Ohm

Cheatsheet Content

### Introduction to Ohm's Law Ohm's Law describes the relationship between voltage, current, and resistance in an electrical circuit. It is a fundamental law in electronics. ### The Formula Ohm's Law is expressed by the formula: $$V = I \times R$$ Where: - $V$ is the **Voltage** (measured in Volts, V) - $I$ is the **Current** (measured in Amperes, A) - $R$ is the **Resistance** (measured in Ohms, $\Omega$) ### Variations of the Formula The formula can be rearranged to solve for any of the three variables: - To find Current ($I$): $$I = \frac{V}{R}$$ - To find Resistance ($R$): $$R = \frac{V}{I}$$ ### Units | Quantity | Symbol | Unit Name | Unit Symbol | |------------|--------|-----------|-------------| | Voltage | V | Volt | V | | Current | I | Ampere | A | | Resistance | R | Ohm | $\Omega$ | ### Ohm's Law Triangle A common mnemonic to remember the formulas is the Ohm's Law Triangle: To use it, cover the variable you want to find, and the remaining two variables show the formula. ### Application Ohm's Law is used to: - Calculate the current flowing through a resistor when voltage is known. - Determine the resistance needed to limit current to a specific value. - Find the voltage drop across a component. ### Limitations - **Linear Resistors:** Ohm's Law applies primarily to linear circuits where resistance is constant regardless of voltage or current. - **Temperature:** Resistance can change with temperature, affecting the accuracy of calculations. - **Non-Ohmic Materials:** Some materials (e.g., semiconductors, diodes) do not obey Ohm's Law.