Quadratic Equation Solver (ax² + bx + c = 0)
About Voltage Calculator
The Electrical Potential & Voltage ($V$) Drop Calculator computes electromotive force using Ohm's Law ($V = IR$), Power equations ($V = P/I = \sqrt{P \cdot R}$), AC RMS voltage ($V_{RMS} = V_{peak}/\sqrt{2}$), Voltage Dividers ($V_{out} = V_{in} \frac{R_2}{R_1+R_2}$), and long-distance wire gauge voltage drops (NEC standard).
How to Use Voltage Calculator
Step 1
Choose calculation mode (Ohm's Law, Voltage Divider, or Cable Voltage Drop).
Step 2
Enter input values (source voltage, current, resistance, or wire length).
Step 3
Review computed potential difference and voltage drop percentage.
Step 4
Click "Copy Voltage Result".
Practical Use Cases for Voltage Calculator
NEC Wire Gauge Sizing & Copper Cable Voltage Drop Analysis
Calculate cable voltage drop percentages across long distances (e.g. 100ft 12 AWG copper run) to maintain NEC 3% branch circuit compliance.
Electronic Voltage Divider & Sensor ADC Scaling Design
Compute precise resistor values ($R_1, R_2$) to step down 12V battery signals into 3.3V/5V microcontroller ADC input ranges.
Input & Output Examples
Calculating Voltage Drop for 120V / 20A Circuit (100ft 10 AWG Copper)
Source: `120 V`, Current: `20 A`, Distance: `100 ft`, Conductor: `10 AWG Copper`
Voltage Drop: `4.08 V (3.40%)` | End Voltage: `115.92 V` | Power Dissipated: `81.6 W` | Recommendation: `Complies with 5% total NEC limit`
Key Features & Performance
- ✓Ohm's Law & Watt's Law Matrix: solve for Voltage from Current, Resistance, or Power.
- ✓NEC Voltage Drop Calculator: incorporates AWG / metric wire sizes, conductor material (Copper, Aluminum), and conduit types.
- ✓Resistor Voltage Divider: computes $V_{out}$, attenuation ratio in decibels (dB), and impedance loading.
- ✓100% Client-Side electrical engine.
- ✓1-Click Copy voltage specifications.
Key Terminology & Definitions
Voltage ($V$)
The difference in electrical potential between two points, representing the electric pressure that drives current through a conductor.
RMS Voltage ($V_{RMS}$)
Root Mean Square voltage; the effective DC-equivalent voltage of an alternating AC sine wave ($V_{RMS} = V_{peak} / \sqrt{2} \approx 0.707 V_{peak}$).