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electrical_engineering_and_electronics_1:block01 [2025/09/27 14:23] – mexleadmin | electrical_engineering_and_electronics_1:block01 [2025/09/29 21:52] (aktuell) – mexleadmin | ||
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===== Learning objectives ===== | ===== Learning objectives ===== | ||
< | < | ||
+ | After this 90-minute block, you can | ||
* Use the SI base quantities, units, and symbols correctly; convert between units with prefixes. | * Use the SI base quantities, units, and symbols correctly; convert between units with prefixes. | ||
* Distinguish base vs. derived quantities; express key EE units (e.g. $\rm V$, $\rm \Omega$) in SI base units. | * Distinguish base vs. derived quantities; express key EE units (e.g. $\rm V$, $\rm \Omega$) in SI base units. | ||
Zeile 34: | Zeile 35: | ||
</ | </ | ||
- | ===== SI base quantities and units ===== | + | ===== Core content ===== |
+ | |||
+ | ==== SI base quantities and units ==== | ||
<WRAP right 50%> | <WRAP right 50%> | ||
< | < | ||
Zeile 67: | Zeile 70: | ||
* The pressure unit bar (${\rm bar}$) is an SI unit. | * The pressure unit bar (${\rm bar}$) is an SI unit. | ||
* BUT: The obsolete pressure unit " | * BUT: The obsolete pressure unit " | ||
- | * To prevent the numerical value from becoming too large or too small, it is possible to replace a decimal factor with a prefix. These are listed in <tabref tab02>. | + | * To prevent the numerical value from becoming too large or too small, it is possible to replace a decimal factor with a prefix. |
We will see, that a lot of electrical quantities are derived quantities. | We will see, that a lot of electrical quantities are derived quantities. | ||
- | ===== Prefixes | + | ==== Prefixes ==== |
<WRAP right 50%> | <WRAP right 50%> | ||
< | < | ||
Zeile 107: | Zeile 110: | ||
~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
- | ===== Physical equations | + | ==== Physical equations ==== |
* Physical equations allow a connection of physical quantities. | * Physical equations allow a connection of physical quantities. | ||
Zeile 117: | Zeile 120: | ||
<WRAP half column> | <WRAP half column> | ||
<callout color=" | <callout color=" | ||
+ | |||
==== Quantity Equations ==== | ==== Quantity Equations ==== | ||
The vast majority of physical equations result in a physical unit that does not equal $1$. | The vast majority of physical equations result in a physical unit that does not equal $1$. | ||
Zeile 131: | Zeile 135: | ||
<WRAP half column> | <WRAP half column> | ||
<callout color=" | <callout color=" | ||
+ | |||
==== normalized Quantity Equations ==== | ==== normalized Quantity Equations ==== | ||
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</ | </ | ||
- | ===== Letters for physical quantities | + | <callout title=" |
+ | |||
+ | Let a body with the mass $m = 100~{\rm kg}$ be given. The body is lifted by the height $s=2~{\rm m}$. \\ | ||
+ | What is the value of the needed work? | ||
+ | |||
+ | \\ \\ | ||
+ | physical equation: | ||
+ | <WRAP indent>< | ||
+ | Work = Force $\cdot$ displacement | ||
+ | \\ $W = F \cdot s \quad\quad\quad\; | ||
+ | \\ $W = m \cdot g \cdot s \quad\quad$ where $m=100~{\rm kg}$, $s=2~m$ and $g=9.81~{{{\rm m}}\over{{\rm s}^2}}$ | ||
+ | \\ $W = 100~kg \cdot 9.81 ~{{{\rm m}}\over{{\rm s}^2}} \cdot 2~{\rm m} $ | ||
+ | \\ $W = 100 \cdot 9.81 \cdot 2 \;\; \cdot \;\; {\rm kg} \cdot {{{\rm m}}\over{{\rm s}^2}} | ||
+ | \\ $W = 1962 \quad\quad \cdot \quad\quad\; | ||
+ | \\ $W = 1962~{\rm Nm} = 1962~{\rm J} $ | ||
+ | </ | ||
+ | |||
+ | </ | ||
+ | |||
+ | ==== Letters for physical quantities ==== | ||
<WRAP right 50%> | <WRAP right 50%> | ||
< | < | ||
Zeile 195: | Zeile 219: | ||
~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
- | ===== Notation & units ===== | + | ==== Notation & units ==== |
The course consistently uses the following symbols, units, and typical values: | The course consistently uses the following symbols, units, and typical values: | ||
Zeile 231: | Zeile 255: | ||
===== Exercises ===== | ===== Exercises ===== | ||
- | ==== Worked example(s) ==== | ||
- | < | + | |
- | **1) Unit check (quantity equation): | + | ==== Quick checks ==== |
- | Show that $P=U\cdot I$ has unit watt. | + | |
+ | # | ||
+ | # | ||
+ | |||
+ | Show that $P=U\cdot I$ has unit watt. (Better to be calulcated after reading Block02) | ||
+ | |||
+ | # | ||
- $[U]=\rm{V}=\rm{kg}\, | - $[U]=\rm{V}=\rm{kg}\, | ||
- $[P]=[U][I]=\rm{kg}\, | - $[P]=[U][I]=\rm{kg}\, | ||
- | </ | + | # |
+ | # | ||
- | < | + | # |
- | **2) Prefix conversion: | + | # |
- | $3.3~\rm{mA}=3.3\times10^{-3}~\rm{A}=3300~\rm{\mu A}$. | + | |
- | </ | + | |
- | < | + | How much energy is needed to lift 100 kg for 2 meters? |
- | **3) Work from lifting (quantity equation): | + | |
- | $W=mgs$ with $m=100~\rm{kg}, | + | |
- | $W=100\cdot9.81\cdot2~\rm{Nm}=1962~\rm{J}$. | + | |
- | </ | + | |
- | ==== Quick checks ==== | + | # |
+ | - $W=mgs$ with $m=100~\rm{kg}, | ||
+ | - $W=100\cdot9.81\cdot2~\rm{Nm}=1962~\rm{J}$ | ||
+ | # | ||
+ | # | ||
# | # | ||
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Convert $47~\rm{k\Omega}$ to $\rm{M\Omega}$ and $\Omega$. | Convert $47~\rm{k\Omega}$ to $\rm{M\Omega}$ and $\Omega$. | ||
- | # | + | # |
$47~\rm{k\Omega}=0.047~\rm{M\Omega}=47{, | $47~\rm{k\Omega}=0.047~\rm{M\Omega}=47{, | ||
# | # | ||
Zeile 268: | Zeile 296: | ||
Is $\eta=\dfrac{P_\rm{O}}{P_\rm{I}}$ dimensionless? | Is $\eta=\dfrac{P_\rm{O}}{P_\rm{I}}$ dimensionless? | ||
- | # | + | # |
Yes. Units cancel ($\rm W/W$); normalized equation. | Yes. Units cancel ($\rm W/W$); normalized equation. | ||
# | # | ||
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Which is larger: $5~\rm{mA}$ or $4500~\rm{\mu A}$? | Which is larger: $5~\rm{mA}$ or $4500~\rm{\mu A}$? | ||
- | # | + | # |
$5~\rm{mA}=5000~\rm{\mu A}$, so $5~\rm{mA}$ is larger. | $5~\rm{mA}=5000~\rm{\mu A}$, so $5~\rm{mA}$ is larger. | ||
Zeile 289: | Zeile 317: | ||
True/False: $1~\rm{V}=1~\rm{Nm/ | True/False: $1~\rm{V}=1~\rm{Nm/ | ||
- | # | + | # |
True (from $W=U \cdot Q$). | True (from $W=U \cdot Q$). | ||
# | # |