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Formula list for DC-Circuits

* The following calculator is for reference only.

1. Ohm’s Law

Voltage (V):

 
? Enter voltage in Volts(V)

Resistance (R):
 
? Enter resistance in Ohms()

Current (I):
Current (I):
 
? Enter current in Amperes(A)

Resistance (R):
 
? Enter resistance in Ohms()

Voltage (V):
Voltage (V):
 
? Enter voltage in Volts(V)

Current (I):
 
? Enter current in Ampere(A)

Resistance (R):

2. Power

Voltage (V):

 
? Enter voltage in Volts(V)

Current (I):
 
? Enter current in Amperes(A)

Power (P):
Current (I):
 
? Enter current in Amperes(A)

Resistance (R):
 
? Enter resistance in Ohms()

Power (P):
Voltage (V):
 
? Enter voltage in Volts(V)

Resistance (R):
 
? Enter resistance in Ohms()

Power (P):

3. 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()

Voltage (V):
Current (I):
 
? Enter current in Amperes(A)

Resistance (R):
 
? Enter resistance in Ohms()

Voltage (V):

4. Current

Voltage (V):

 
? Enter voltage in Volts(V)

Resistance (R):
 
? Enter resistance in Ohms()

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()

Current (I):

5. 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):

6. Efficiency

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

 
? Enter power out

Power in:
 
? Enter power in

Efficiency (η):

7. Resistance

R = (ρl)/A
Resistivity (ρ):

 
? Resistivity in ohm-meters, if resistivity is given as 1.72 x 10-8 then type 0.0000000172 in this box

Length (l):
 
? Enter length in meters

Cross-sectional area (A):
 
? Enter cross-sectional area and select the given unit,either m2 or mm2
m2 mm2

Resistance (R):

8. Resistance at new temperature

R = Rref (1 + α (T – Tref))
Resistance (Rref):

 
? Resistance at reference temperature (Tref) in Ω

Temperature coefficient (α):
 
? If the temp coefficient is given as 3.92 x 10-3 then type 0.00392 in this box

New temperature (T):
 
? New temperature

Reference temperature (Tref):
 
? Temperature reference Tref

Resistance (R):

9. Conductance

Conductance: G = 1 / R
Resistance (R):
 
? Resistance (R)

Conductance (G):