# Formula list for D.c Circuits

* This calculator is a quick reference, they might have some errors.

## Ohm's Law

 Voltage (V): ? Enter voltage in Volts(V) Resistance (R): ? Enter resistance in Ohms(Ω)
 Current (I):
 Current (I): ? Enter current in Amperes(A) Resistance (R): ? Enter resistance in Ohms(Ω)
 Voltage (V):
 Voltage (V): ? Enter voltage in Volts(V) Current (I): ? Enter current in Ampere(A)
 Resistance (R):

## Power

Voltage (V): ? Enter voltage in Volts(V) ? Enter resistance in Ohms(Ω)
Current (I): ? Enter current in Amperes(A) ? Enter resistance in Ohms(Ω)
Voltage (V): ? Enter voltage in Volts(V) ? Enter current in Ampere(A)

## Voltage

Power (P): ? Enter power in Watts(W) ? Enter current in Amperes(A)
Power (P): ? Enter power in Watts(W) ? Enter resistance in Ohms(Ω)
Current (I): ? Enter current in Amperes(A) ? Enter resistance in Ohms(Ω)

## Current

Voltage (V): ? Enter voltage in Volts(V) ? Enter resistance in Ohms(Ω)
Power (P): ? Enter current in Amperes(A) ? Enter voltage in Volts(V)
Power (P): ? Enter power in Watts(W) ? Enter resistance in Ohms(Ω)

## Resistance

Voltage (V): ? Enter voltage in Volts(V) ? Enter current in Amperes(A)
Power (P): ? Enter power in Watts(W) ? Enter current in Amperes(A)
Voltage (V): ? Enter voltage in Volts(V) ? Enter current in Ampere(A)

## Efficiency

η = (power out / power in) ×100%
Power out: ? Enter power out ? Enter power in

### Cable resistance and conductance

R = (ρl)/A
Resistivity (ρ): ? Enter resistivity in ohm-meters ? Enter length in meters ? Enter cross-sectional area in square meters
R = Rref (1 + α (T - Tref))
Resistance (Rref): ? Resistance at reference temperature (Tref) ? Temperature coefficient at Tref ? Temperature ? Temperature reference Tref
Conductance: G = 1 / R
Resistance (R): ? Resistance (R)
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