# Basic Electrical Engineering

## Basic Electrical Formula:

The most common used electrical formulas – Ohms Law and combinations. Common electrical units used in formulas and equations are

### Electrical Voltage – 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 = V^{2}/ P(3b)

R = P / I^{2}(3c)

### Electric Power

P = V I(4a)

P = R I^{2}(4b)

P = V^{2}/ R(4c)

where

P = power (watts, W, J/s)

V = voltage (volts, V)

I= current (amperes, A)

R= resistance (ohms, Ω)

### Electric Energy

Electric energy is power multiplied with time:

*W = P t (5)*

*where*

*W = energy (Ws, J)*

*t = time (s)*

Alternative – power can be expressed

*P = W / t (5b)*

Power is consumption of energy by consumption of time.