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Formula list for D.c Circuits

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

Ohm’s Law




Voltage (V):

 
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Enter voltage in Volts(V)
Resistance (R):  
?
Enter resistance in Ohms(Ω)
Current (I):
Current (I):  
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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):

 
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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:

 
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Enter power out
Power in:  
?
Enter power in
Efficiency (η):

Cable resistance and conductance


R = (ρl)/A

Resistivity (ρ):

 
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Enter resistivity in ohm-meters
Length (l):  
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Enter length in meters
Cross-sectional area (A):  
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Enter cross-sectional area in square meters
Resistance (R):


R = Rref (1 + α (T – Tref))

Resistance (Rref):

 
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Resistance at reference temperature (Tref)
Temp coefficient (α):  
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Temperature coefficient at Tref
Temperature (T):  
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Temperature
Temperature reference (Tref):  
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Temperature reference Tref
Resistance (R):


Conductance: G = 1 / R

Resistance (R):  
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Resistance (R)
Conductance (G):