Quadratic Equation Solver (ax² + bx + c = 0)
About Current Calculator
The Electric Current & Amperage ($I$) Calculator computes electric current flow using Ohm's Law ($I = V/R$), Electrical Power ($I = P/V = \sqrt{P/R}$), Kirchhoff's Current Law (KCL), Current Dividers ($I_1 = I_{total} \frac{R_2}{R_1+R_2}$), and battery runtime discharge rates ($t = \text{Capacity} / I$).
How to Use Current Calculator
Step 1
Select calculation type (Ohm's Law, Appliance Amperage, or LED Current Limiter).
Step 2
Enter Voltage, Power, or Resistance values.
Step 3
Review computed current in Amperes (A), Milliamperes (mA), and recommended breaker rating.
Step 4
Click "Copy Amperage".
Practical Use Cases for Current Calculator
Circuit Breaker & Electrical Panel Amperage Sizing
Calculate continuous electrical current draw (Amperes) to correctly size 15A, 20A, 30A, and 50A circuit breakers according to the 80% continuous load rule.
Battery Runtime & LED Series Current Limiting
Determine lithium battery discharge hours ($C/I$) and compute series current-limiting resistors ($R = (V_s - V_f)/I_{LED}$) for LEDs.
Input & Output Examples
Calculating Current for 1500W Space Heater at 120V
Power: `1500 W`, Voltage: `120 V`
Current (I): `12.50 Amperes` | Minimum Breaker: `15 A (Standard)` / `20 A (Continuous)` | Resistance: `9.60 Ω`
Key Features & Performance
- ✓Solves for Current ($I$) via: $V/R$, $P/V$, $\sqrt{P/R}$, Single/Three-Phase AC power.
- ✓LED Resistor & Current Limiter Designer: computes required resistor ohms and wattage rating.
- ✓Battery Runtime Estimator: incorporates Peukert's law for lead-acid and lithium battery discharge curves.
- ✓100% Client-Side memory execution.
- ✓1-Click Copy amperage results.
Key Terminology & Definitions
Electric Current ($I$)
The rate of flow of electric charge through a conductor, measured in Amperes ($1\text{ A} = 1\text{ Coulomb per second}$).
80% Continuous Load Rule
A safety standard requiring that electrical circuits running continuously for 3+ hours must not exceed 80% of the breaker rating (e.g. 12A max on a 15A circuit).