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## Farad
Measures capacitance, the ability of a body to store an electrical charge.
1 Farad = the ability to store 1 couloumb
Term | Symbol | Weight
-----------|----|------
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Picofarad | pF | $10^{-12}$
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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
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# 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 $10 \rightarrow 100$
