ELECTRICAL Tools

ELECTOOLS

⚡ Ohm's Law

⚡ Ohm's Law

Fill any two fields — the third is calculated automatically.

Voltage (V)

Current (A)

Resistance (Ω)

Voltage (V)—V

Current (I)—A

Resistance (R)—Ω

Power (P = V×I)—W

🔀 Voltage Divider

Vout = Vin × R2 / (R1 + R2)

Input Voltage Vin (V)

R1 — top resistor (Ω)

R2 — bottom resistor (Ω)

Output Voltage (Vout)—V

Divider Ratio—%

Total Resistance—Ω

Current through divider—mA

🔴 Resistor Color Code

Resistance—Ω

Tolerance—%

Range—Ω

🔋 Capacitor Charge

RC charging: Vc(t) = V × (1 − e^(−t/τ))

Capacitance (µF)

Resistance (Ω)

Supply Voltage (V)

Time Constant (τ)—

63.2% Charge (1τ)—V

86.5% Charge (2τ)—V

95.0% Charge (3τ)—V

99.3% Charge (5τ)—V

Fully Charged (~5τ)—ms

💡 Power Calculator

Voltage (V)

Current (A)

Power—W

Energy per hour—Wh

Energy per day—kWh

➕ Series / Parallel Resistors

R_total = R1 + R2 + … + Rn

R1 (Ω)

R2 (Ω)

R3 (Ω)

Total Resistance—Ω

🔆 LED Resistor Calculator

R = (Vs − Vf) / I

Supply Voltage Vs (V)

LED Forward Voltage Vf (V)

LED Current (mA)

Exact Resistor Value—Ω

Nearest Standard (E12)—Ω

Power Dissipated—mW

Voltage Drop across R—V

〰️ RC Cutoff Frequency

f = 1 / (2π × R × C)

Resistance (Ω)

Capacitance (nF)

Cutoff Frequency (−3dB)—

Time Constant (τ)—µs

Angular Frequency (ω)—rad/s

Period—ms

🔁 Unit Converter

Category VoltageCurrentResistance CapacitanceInductancePowerFrequency

Value

From