1. What is a Resistor Value Calculator?

Definition: This calculator determines the required resistance value based on Ohm's Law, which relates voltage, current, and resistance in an electrical circuit.

Purpose: It helps electronics engineers, technicians, and hobbyists select the appropriate resistor for their circuits.

2. How Does the Calculator Work?

The calculator uses Ohm's Law formula:

Where:

• \( R \) — Resistance (ohms)
• \( V \) — Voltage (volts)
• \( I \) — Current (amps)

Explanation: The voltage is divided by the current to determine the required resistance value.

3. Importance of Resistor Calculation

Details: Proper resistor selection ensures correct current flow, prevents component damage, and maintains circuit stability.

4. Using the Calculator

Tips: Enter the voltage across the resistor and the desired current through it. Current must be greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What if I get a non-standard resistor value?
A: Use the next higher standard resistor value or combine resistors in series/parallel to achieve the desired value.

Q2: How do I account for resistor tolerance?
A: Standard resistors have 5% or 10% tolerance. Choose a value that keeps your actual current within acceptable limits.

Q3: What about power rating?
A: Calculate power using P = V×I and select a resistor with wattage rating higher than your calculated value.

Q4: Can I use this for AC circuits?
A: This calculator works for DC circuits. For AC, you need to consider impedance which includes reactance.

Q5: What if my current is in milliamps?
A: Convert milliamps to amps by dividing by 1000 before entering the value (10mA = 0.01A).