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) | |
|---|---|---|
| Resistance (R): | ? Enter resistance in Ohms(Ω) |
| Power (P): |
|---|
| Current (I): | ? Enter current in Amperes(A) | |
|---|---|---|
| Resistance (R): | ? Enter resistance in Ohms(Ω) |
| Power (P): |
|---|
| Voltage (V): | ? Enter voltage in Volts(V) | |
|---|---|---|
| Current (I): | ? Enter current in Ampere(A) |
| Power (P): |
|---|
Voltage
| Power (P): | ? Enter power in Watts(W) | |
|---|---|---|
| Current (I): | ? Enter current in Amperes(A) |
| Voltage (V): |
|---|
| Power (P): | ? Enter power in Watts(W) | |
|---|---|---|
| Resistance (R): | ? Enter resistance in Ohms(Ω) |
| Voltage (V): |
|---|
| Current (I): | ? Enter current in Amperes(A) | |
|---|---|---|
| Resistance (R): | ? Enter resistance in Ohms(Ω) |
| Voltage (V): |
|---|
Current
| Voltage (V): | ? Enter voltage in Volts(V) | |
|---|---|---|
| Resistance (R): | ? Enter resistance in Ohms(Ω) |
| Current (I): |
|---|
| Power (P): | ? Enter current in Amperes(A) | |
|---|---|---|
| Voltage (V): | ? Enter voltage in Volts(V) |
| Current (I): |
|---|
| Power (P): | ? Enter power in Watts(W) | |
|---|---|---|
| Resistance (R): | ? Enter resistance in Ohms(Ω) |
| Current (I): |
|---|
Resistance
| Voltage (V): | ? Enter voltage in Volts(V) | |
|---|---|---|
| Current (I): | ? Enter current in Amperes(A) |
| Resistance (R): |
|---|
| Power (P): | ? Enter power in Watts(W) | |
|---|---|---|
| Current (I): | ? Enter current in Amperes(A) |
| Resistance (R): |
|---|
| Voltage (V): | ? Enter voltage in Volts(V) | |
|---|---|---|
| Power (P): | ? Enter current in Ampere(A) |
| Resistance (R): |
|---|
Efficiency
η = (power out / power in) ×100%
| Power out: | ? Enter power out | |
|---|---|---|
| Power in: | ? Enter power in |
| Efficiency (η): |
|---|
Cable resistance and conductance
R = (ρl)/A
| Resistivity (ρ): | ? Enter resistivity in ohm-meters | |
|---|---|---|
| Length (l): | ? Enter length in meters | |
| Cross-sectional area (A): | ? Enter cross-sectional area in square meters |
| Resistance (R): |
|---|
R = Rref (1 + α (T - Tref))
| Resistance (Rref): | ? Resistance at reference temperature (Tref) | |
|---|---|---|
| Temp coefficient (α): | ? Temperature coefficient at Tref | |
| Temperature (T): | ? Temperature | |
| Temperature reference (Tref): | ? Temperature reference Tref |
| Resistance (R): |
|---|
Conductance: G = 1 / R
| Resistance (R): | ? Resistance (R) |
|---|
| Conductance (G): |
|---|