## Farad
Measures capacitance, the ability of a body to store an electrical charge.
1 Farad = the ability to store 1 couloumb

Term | Symbol | Weight
-----------|----|------
 Picofarad  | pF | $10^{-12}$
 Nanofarad  | nF | $10^{-9}$
 Microfarad | $\micro$F | $10^{-6}$
 Milifarad  | mF | $10^{-3}$
 Farad      | F  | $10^0$
 Kilofarad  | kF | $10^{3}$

## Couloumb
1 coulomb is the electric charge transported within one second through the cross-section of a conductor in which an electric current of the strength of 1 ampere flows.

## Henry
Measures electrical Inductance

$\displaystyle V(t)=L{\frac {dI}{dt}}$

## Volts
Measures electric potential

## Amperes
Measures electric current

## Ohms
Measures resistance

Term | Symbol | Weight
-----------|----|------
 Nanoohm  | n$\ohm$ | 10-9
 Microohm | $\micro \ohm$ | $10^{-6}$
 Milliohm | m$\ohm$ | $10^{-3}$
 Ohm      | $\ohm$  | $10^{0}$
 Kiloohm  | k$\ohm$ | $10^{3}$
 Megaohm  | M$\ohm$ | $10^{6}$
 Gigaohm  | G$\ohm$ | $10^{9}$

## Hertz

Measures frequency

Term      | Symbol | Weight
----------|------- | -----
Hertz     | Hz     | $10^0$
Kilohertz | kHz    | $10^{3}$
Megahertz | mHz    | $10^6$


## Watt
Measures Power

$Power = V * I = \frac{V^{2}}{R} = I^{2}R$ 

Joules per Second

Term | Symbol | Weight
-----------|----|------
 Nanowatt  | nW | $10^{-9}$
 Microwatt | $\micro$W | $10^{-6}$
 Milliwatt | mW | $10^{-3}$
 Watt      | W  | $10^{0}$
 Kilowatt  | kW | $10^{3}$
 Megawatt  | MW | $10^{6}$
 Gigawatt  | GW | $10^{9}$

**Examples:**

Device | Power
-------|----------
Arduino| 167mW
Laptop | 1.5W
House  | 2.2kW


# Decibel

A decibel ($dB$) is used to describe the ratio between two values, it is calculated as $\displaystyle 10\log{10}{\frac{V1}{V2}}$

Here are a few commonly used values

| db Value | Power Ratio (10logA) | Voltage/CurrentRatio (20log(A)) |
| ---- | --- | ---- |
| -20dB | 0.01 | 0.1 |
| -10dB | 0.1 | 0.3162 |
| -6dB | 0.25 | 1/2 = 0.5 |
| -3dB |1/2 = 0.5 | $1\sqrt{2} \approx 0.707$ |
| -1dB | 0.79 | 0.89 |
| 0dB | 1 | 1 |
| 1dB | 1.26 | 1.1 |
| 3dB | 2 | $\sqrt{2} \approx 1.414$ |
| 6dB | 4 | 2 |
| 10dB | 10 | $\sqrt{10} \approx 3.162$ |
| 20dB | 100 | 10 |
| 30dB | 1000 | 31.62 |

# Decade
Related to Frequencies

One decade is a distance along the frequency line, for example  $1 \rightarrow 10$ or $10 \rightarrow 100$