Elektronica formules (Engels)

in amperes A

Resistance R = V / I = P / I2 = V2 / P in ohms Ω    

Power P = V × I = R × I2 = V2 / R in watts W

Electrical Potential – Ohm’s Law

Ohm’s law can be expressed as:

V = R I         (1a)

V = P / I         (1b)

V = (P R)1/2         (1c)

Electric Current – Ohm’s Law

I = V / R         (2a)

I = P / V         (2b)

I = (P / R)1/2         (2c)

Electric Resistance – Ohm’s Law

R = V / I         (3a)

R = V2/ P         (3b)

R = P / I2         (3c)

Electric Power

P = V I         (4a)

P = R I2         (4b)

P = V2/ R         (4c)

where

P = power (watts, W), V = voltage (volts, V)

I = current (amperes, A), R = resistance (ohms, Ω)

Electric Energy :Electric energy is power multiplied time, or

W = P t      (5)

where

W = energy (Ws, J), t = time (s)

Electrical Motors : Electrical Motor Efficiency

μ = 746 Php / Pinput_w         (6)

where

μ = efficiency

Php = output horsepower (hp)

Pinput_w = input electrical power (watts)

or alternatively

μ = 746 Php / (1.732 V I PF)         (6b)

Electrical Motor – Power

P3-phase = (V I PF 1.732) / 1,000         (7)

where

P3-phase = electrical power 3-phase motor (kW)

PF = power factor electrical motor

Electrical Motor – Amps

I3-phase = (746 Php) / (1.732 V μ PF)         (7)

where

I3-phase = electrical current 3-phase motor (amps)

PF = power factor electrical motor

Electrical measurements

Quantity

Name

Definition

frequency f

hertz (Hz)

1/s

force F

newton (N)

kg•m/s²

pressure p

pascal (Pa) = N/m²

kg/m•s²

energy E

work joule (J) = N•m

kg•m²/s²

power P

watt (W) = J/s

kg•m²/s³

electric charge Q

coulomb (C) = A•s

A•s

voltage V

volt (V)= W/A

kg•m²/A•s³

current I

ampere (A) = Q/s

A

capacitance C

farad (F) = C/V = A•s/V = s/Ω

A²•s4/kg•m²