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electrical_engineering_1:non-ideal_sources_and_two_terminal_networks [2023/12/03 16:59] mexleadmin |
electrical_engineering_1:non-ideal_sources_and_two_terminal_networks [2023/12/04 00:22] (aktuell) mexleadmin |
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Another example is a $1.5~\rm V$ battery: If such a battery is short-circuited by a piece of wire, not so much current flows that the piece of wire glows, but noticeably less. | Another example is a $1.5~\rm V$ battery: If such a battery is short-circuited by a piece of wire, not so much current flows that the piece of wire glows, but noticeably less. | ||
- | So it makes sense here to develop the concept of the ideal voltage source further. In addition, we will see that this also opens up a possibility | + | So it makes sense here to develop the concept of the ideal voltage source further. In addition, we will see that this also opens up the possibility |
< | < | ||
Zeile 387: | Zeile 387: | ||
~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
- | ===== Exercises | + | |
+ | ==== Exercises ==== | ||
<panel type=" | <panel type=" | ||
Zeile 435: | Zeile 436: | ||
For the company „HHN Mechatronics & Robotics“ you shall analyze a competitor product: a simple drilling machine. This contains a battery pack, some electronics, | For the company „HHN Mechatronics & Robotics“ you shall analyze a competitor product: a simple drilling machine. This contains a battery pack, some electronics, | ||
- | The drill has two speed modes: | + | The drill has two speed-modes: |
- max power: here, the motor is directly connected to the battery. | - max power: here, the motor is directly connected to the battery. | ||
- reduced power: in this case, a shunt resistor $R_{\rm s} = 1 ~\Omega$ is connected in series to the motor. | - reduced power: in this case, a shunt resistor $R_{\rm s} = 1 ~\Omega$ is connected in series to the motor. | ||
Zeile 454: | Zeile 455: | ||
</ | </ | ||
- | # | + | # |
Two heater resistors (both with $R_\rm L = 0.5 ~\Omega$) shall be supplied with two lithium-ion-batteries (both with $U_{\rm S} = 3.3 ~\rm V$, $R_{\rm i} = 0.1 ~\Omega$). | Two heater resistors (both with $R_\rm L = 0.5 ~\Omega$) shall be supplied with two lithium-ion-batteries (both with $U_{\rm S} = 3.3 ~\rm V$, $R_{\rm i} = 0.1 ~\Omega$). | ||
1. What are the possible ways to connect these components? | 1. What are the possible ways to connect these components? | ||
+ | |||
+ | # | ||
+ | {{drawio> | ||
+ | # | ||
2. Which circuit can provide the maximum power $P_{\rm L ~max}$ at the loads? | 2. Which circuit can provide the maximum power $P_{\rm L ~max}$ at the loads? | ||
+ | |||
+ | # | ||
+ | |||
+ | At the maximum utilization rate $\varepsilon = 0.25$ the maximum power $P_{\rm L ~max}$ can be achieved. \\ | ||
+ | The utilization rate is given as: | ||
+ | \begin{align*} | ||
+ | \varepsilon &= {{P_{\rm out}}\over{P_{\rm in, max}}} | ||
+ | &= {{R_{\rm L}\cdot R_{\rm i}} \over {(R_{\rm L}+R_{\rm i})^2}} \\ | ||
+ | \end{align*} | ||
+ | |||
+ | As near the resulting equivalent internal resistance approaches the resulting equivalent load resistance, as higher the utilization rate $\varepsilon$ will be.\\ | ||
+ | Therefore, a series configuration of the batteries ($2 R_{\rm i} = 0.2~\Omega$) and a parallel configuration of the load (${{1}\over{2}} R_{\rm L}= 0.25~\Omega$) will have the highest output. | ||
+ | # | ||
+ | |||
+ | # | ||
+ | The following configuration has the maximum output power. | ||
+ | |||
+ | {{drawio> | ||
+ | # | ||
+ | |||
3. What is the value of the maximum power $P_{\rm L ~max}$? | 3. What is the value of the maximum power $P_{\rm L ~max}$? | ||
+ | |||
+ | # | ||
+ | The maximum utilization rate is: | ||
+ | \begin{align*} | ||
+ | \varepsilon &= {{{{1}\over{2}} R_{\rm L} \cdot 2 R_{\rm i} } \over { ({{1}\over{2}} R_{\rm L} + 2 R_{\rm i} )^2}} \\ | ||
+ | &= { {0.25 ~\Omega | ||
+ | &= 24.6~\% | ||
+ | \end{align*} | ||
+ | |||
+ | Therefore, the maximum power is: | ||
+ | \begin{align*} | ||
+ | \varepsilon | ||
+ | \rightarrow P_{\rm out} &= \varepsilon | ||
+ | & | ||
+ | & | ||
+ | \end{align*} | ||
+ | |||
+ | # | ||
+ | |||
+ | # | ||
+ | \begin{align*} | ||
+ | P_{\rm out} = 26.8 W | ||
+ | \end{align*} | ||
+ | # | ||
4. Which circuit has the highest efficiency? | 4. Which circuit has the highest efficiency? | ||
+ | |||
+ | # | ||
+ | The highest efficiency $\eta$ is given when the output power compared to the input power is minimal. \\ | ||
+ | A parallel configuration of the batteries (${{1}\over{2}} R_{\rm i} = 0.05~\Omega$) and a series configuration of the load ($2 R_{\rm L}= 1.0~\Omega$) will have the highest efficiency. | ||
+ | # | ||
+ | |||
+ | # | ||
+ | {{drawio> | ||
+ | # | ||
5. What is the value of the highest efficiency? | 5. What is the value of the highest efficiency? | ||
+ | |||
+ | # | ||
+ | The efficiency $\eta$ is given as: | ||
+ | \begin{align*} | ||
+ | \eta &= { {2 R_{\rm L} }\over{ 2 R_{\rm L}+ {{1}\over{2}} R_{\rm i} }} \\ | ||
+ | &= { { 1.0~\Omega }\over{ 1.0~\Omega + 0.05~\Omega }} | ||
+ | \end{align*} | ||
+ | |||
+ | # | ||
+ | |||
+ | # | ||
+ | \begin{align*} | ||
+ | \eta = 95.2~\% | ||
+ | \end{align*} | ||
+ | # | ||
+ | \\ \\ | ||
+ | # | ||
+ | {{drawio> | ||
+ | |||
+ | # | ||
+ | |||
# | # |