Parallel Circuits :
Note 1: Total resistance is always less than the smallest resistor RT = 1/(1/R1+ 1/R2+ 1/R3+ ...)
Note 2: Total current is equal to the sum of the currents of all parallel resistors
Note 3: Total power is equal to the sum of power of all parallel resistors
Note 4: Voltage is the same across each of the parallel resistors
Series Circuits :
Note 1: Total resistance is equal to the sum of all the resistors
Note 2: Current in the circuit remains the same through all the resistors
Note 3: Voltage source is equal to the sum of voltage drops of all resistors
Note 4: Power of the circuit is equal to the sum of the power of all resistors
Considering 50Hz frequency:
Capacitive Reactance (Xc) in Ohms = 1/(2πf C)
Inductive Reactance (XL) in Ohms = 2π f L
Effective (RMS) AC Amperes = Peak Amperes x 0.707
Effective (RMS) AC Volts = Peak Volts x 0.707
Peak AC Volts = Effective (RMS) AC Volts x 2
Peak Amperes = Effective (RMS) Amperes x 2
Power Factor (PF) = Watts/VA
VA (apparent power) = Volts x Ampere or Watts/Power Factor
VA 1-Phase = Volts x Amperes
VA 3-Phase = Volts x Amperes x 3
Watts (real power) Single-Phase = Volts x Amperes x Power Factor
Watts (real power) Three-Phase = Volts x Amperes x Power Factor x3
Formula for Efficiency:
Input = Output/Efficiency
Output = Input x Efficiency
Efficiency (%) = Output/Input x 100
Efficiency = Output/Input
Horsepower = Output Watts/746
For more see:Electrical formula Part-II
Note 1: Total resistance is always less than the smallest resistor RT = 1/(1/R1+ 1/R2+ 1/R3+ ...)
Note 2: Total current is equal to the sum of the currents of all parallel resistors
Note 3: Total power is equal to the sum of power of all parallel resistors
Note 4: Voltage is the same across each of the parallel resistors
Series Circuits :
Note 1: Total resistance is equal to the sum of all the resistors
Note 2: Current in the circuit remains the same through all the resistors
Note 3: Voltage source is equal to the sum of voltage drops of all resistors
Note 4: Power of the circuit is equal to the sum of the power of all resistors
Considering 50Hz frequency:
Capacitive Reactance (Xc) in Ohms = 1/(2πf C)
Inductive Reactance (XL) in Ohms = 2π f L
Effective (RMS) AC Amperes = Peak Amperes x 0.707
Effective (RMS) AC Volts = Peak Volts x 0.707
Peak AC Volts = Effective (RMS) AC Volts x 2
Peak Amperes = Effective (RMS) Amperes x 2
Power Factor (PF) = Watts/VA
VA (apparent power) = Volts x Ampere or Watts/Power Factor
VA 1-Phase = Volts x Amperes
VA 3-Phase = Volts x Amperes x 3
Watts (real power) Single-Phase = Volts x Amperes x Power Factor
Watts (real power) Three-Phase = Volts x Amperes x Power Factor x3
Formula for Efficiency:
Input = Output/Efficiency
Output = Input x Efficiency
Efficiency (%) = Output/Input x 100
Efficiency = Output/Input
Horsepower = Output Watts/746
For more see:Electrical formula Part-II