1. What is a Resistor Calculator?

Definition: This calculator determines the resistance needed in a circuit based on Ohm's Law, using voltage and current values.

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 current to calculate the required resistance.

3. Importance of Resistance Calculation

Details: Proper resistance calculation ensures circuit protection, correct current flow, and optimal component performance.

4. Using the Calculator

Tips: Enter the voltage in volts and current in amps. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What if I know resistance and want to find voltage or current?
A: Use the variations of Ohm's Law: \( V = I \times R \) or \( I = \frac{V}{R} \).

Q2: What's a typical voltage range for small electronics?
A: Common voltages are 3.3V, 5V, 9V, or 12V for most small electronic circuits.

Q3: How precise do I need to be with resistor values?
A: Standard resistors have 5% or 1% tolerance. Choose the nearest standard value higher than your calculation.

Q4: What if my current is in milliamps?
A: Convert milliamps to amps by dividing by 1000 before entering the value (e.g., 500mA = 0.5A).

Q5: Does this account for power rating?
A: No, you must separately calculate power (P = V × I) to ensure the resistor can handle the wattage.