WienerDog Engineering · deterministic calculators

Electrical & Electronics Calculator Center

Fast circuit and wiring math without an AI call. Solve Ohm's law, estimate voltage drop and conductor resistance, size LED resistors, work with dividers and resistor networks, estimate battery runtime, calculate RC timing, transformer ratios and three-phase power.

Ohm's Law Voltage Drop AWG Wire LED Resistor Voltage Divider Battery Runtime Resistor Network RC Timing Transformer 3-Phase Power

V · I · R · P

Ohm's Law & Power Solver

Known values

Voltage (V)Resistance (Ω)

Wiring estimate

Voltage Drop

SystemConductorAWG

Source voltage (V)Current (A)One-way length (ft)Conductor temp (°C)

Voltage-drop math only. This does not determine allowable ampacity, insulation rating, raceway fill, breaker/fuse size, derating or code compliance. Verify the applicable electrical code and equipment requirements for the installation.

Geometry & resistance

AWG Wire Reference

ConductorAWGLength (ft)

Conductor temperature (°C)

Resistance is calculated from AWG diameter, conductor cross-sectional area and material resistivity. Real cable resistance varies with alloy, stranding and temperature.

Current limiting

LED Series Resistor

Supply voltage (V)LED forward voltage (V each)LEDs in seriesDesired current (mA)

Use the LED manufacturer's forward-voltage/current data. For power LEDs or changing supply voltages, a constant-current driver may be more appropriate than a resistor.

Two-resistor divider

Voltage Divider

Input voltage (V)R1 — top (Ω)R2 — bottom (Ω)

This is the unloaded divider result. A connected load in parallel with R2 changes the output voltage.

Energy estimate

Battery Runtime

Nominal voltage (V)Capacity (Ah)Load (W)Overall efficiency (%)

Usable capacity (%)

A planning estimate only. Actual runtime depends on battery chemistry, discharge rate, age, temperature, inverter behavior and cutoff voltage.

Network equivalent

Series & Parallel Resistors

Resistance values (Ω, separated by commas)

Time & frequency

RC Time Constant & Cutoff

ResistanceR unitCapacitanceC unit

Ideal transformer

Transformer Ratio

Primary voltage (V)Secondary voltage (V)Primary turns

Secondary load current (A)

Ideal-transformer math; it does not include winding resistance, core losses, regulation, saturation or thermal limits.

Balanced 3-phase

Three-Phase Power

Line-to-line voltage (V)Line current (A)Power factorEfficiency (%)

Assumes a balanced three-phase load. The efficiency field estimates delivered output power from electrical real power.

Keep exploring

For related calculations, explore the Calculator Center and unit converter.

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