# Frequency

Written by Jerry Ratzlaff on . Posted in Electrical Engineering

Frequency, abbreviated as f or FREQ, is the number of times an alternating current reverses itself in one second.  Expressed in Hertz (Hz), which is one cycle per second.

Frequency (Probability), is the rate of occurrence.

## Frequency formulas

 $$\large{ f = \frac { 1 } { T } }$$ $$\large{ f = \frac { N_c } { t } }$$ $$\large{ f = \frac{v}{ \lambda } }$$ $$\large{ f = \frac{c}{ \lambda } }$$ $$\large{ f = \frac{\omega}{ 2 \; \pi } }$$

### Where:

$$\large{ f }$$ = frequency

$$\large{ \omega }$$  (Greek symbol omega) = angular frequency

$$\large{ N_c }$$ = number of cycles

$$\large{ \pi }$$ = Pi

$$\large{ c }$$ = speed of light

$$\large{ t }$$ = time

$$\large{ T }$$ = time period, the time required for one cycle or wave occillation

$$\large{ \lambda }$$  (Greek symbol \lambda) = wavelength

$$\large{ v }$$ = wavelength velocity

## Frequency (Probability) formulas

 $$\large{ f_x = \frac { n_x } { n } }$$ $$\large{ P_x = \frac { f_x } { f_a } }$$

### Where:

$$\large{ f_x }$$ = relative frequency of outcome x

$$\large{ P_x }$$ = probability of outcome x

$$\large{ f_a }$$ = frequency of all events

$$\large{ n_x }$$ = number of events with outcome x

$$\large{ n }$$ = total number of events