Engineering Equation & Reference
Calculate exact and nearest standard E12 current-limiting resistor values and power ratings for single or series LED strings.
Electronics Calculators
LED Series Current-Limiting Resistor & Wattage Calculator (with E12)
Calculate exact and nearest standard E12 current-limiting resistor values and power ratings for single or series LED strings.
Related Engineering Calculators
Electronics Calculators
4-Band & 5-Band Resistor Color Code Calculator (Visual EIA Chart)
Interactive visual 4-band and 5-band resistor color decoder showing live painted resistor bands, exact resistance, and min/max tolerance range.
R_4band = (10·D₁ + D₂) × Multiplier ± Tolerance%
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Electronics Calculators
Ohm's Law & Joule Electrical Power Calculator (V, I, R, P)
Instantaneous solver for electric current, power dissipation in watts, conductance in siemens, and hourly energy consumption.
I = V / R, P = V × I = I²R = V² / R
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Electronics Calculators
Resistive Voltage Divider & Thevenin Impedance Calculator
Compute divided output voltage Vout, decibel attenuation, bleeder current, and Thevenin equivalent output resistance Rth.
Vout = Vin × R₂ / (R₁ + R₂), Rth = (R₁ × R₂) / (R₁ + R₂)
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Electronics Calculators
Parallel & Series Equivalent Resistor Network Calculator
Compute exact parallel and series equivalent resistance for two or three resistor combinations simultaneously.
1 / R_parallel = 1/R₁ + 1/R₂ + 1/R₃, R_series = R₁ + R₂ + R₃
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Electronics Calculators
Capacitors in Series & Parallel Calculator (+ Charge & Energy)
Calculate total capacitance for parallel banks and series strings along with stored coulombs Q and electrostatic energy.
C_parallel = C₁ + C₂, C_series = (C₁ × C₂) / (C₁ + C₂)
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AC & RF Calculators
RC Filter Cutoff Frequency (-3 dB), Gain & Phase Shift Calculator
Compute −3 dB corner frequency fc, time constant τ, attenuation in dB, and exact phase shift angle at any operating frequency.
fc = 1 / (2πRC), τ = R × C, φ = −arctan(f / fc)
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