Unterschiede
Hier werden die Unterschiede zwischen zwei Versionen angezeigt.
Beide Seiten der vorigen Revision Vorhergehende Überarbeitung Nächste Überarbeitung | Vorhergehende Überarbeitung | ||
circuit_design:1_amplifier_basics [2023/01/31 10:08] mexleadmin |
circuit_design:1_amplifier_basics [2023/12/16 01:12] (aktuell) mexleadmin [Bearbeiten - Panel] |
||
---|---|---|---|
Zeile 1: | Zeile 1: | ||
- | ====== 1. Amplifier Basics ====== | + | ====== 1 Amplifier Basics ====== |
- | ===== 1.0 What is circuit design? ===== | + | ===== 1.0 What is Circuit Design? ===== |
< | < | ||
< | < | ||
- | {{drawio> | + | {{drawio> |
</ | </ | ||
Circuit design encompasses various subfields of electronics. | Circuit design encompasses various subfields of electronics. | ||
- | <imgref tablelabel> | + | <imgref tablelabel> |
In the subject [[Introduction to digital Systems: | In the subject [[Introduction to digital Systems: | ||
Zeile 15: | Zeile 15: | ||
Circuit design now concentrates on __electr**on**ic components and their circuits__ that affect analog electronics. | Circuit design now concentrates on __electr**on**ic components and their circuits__ that affect analog electronics. | ||
- | These components and circuits often connect the digital with the analog world or adjust voltages and currents for other sub-circuits. In addition, the components " | + | These components and circuits often connect the digital with the analog world or adjust voltages and currents for other sub-circuits. In addition, the components " |
=== Circuit Design and Electronics === | === Circuit Design and Electronics === | ||
But what is the difference between electronics and electrical engineering? | But what is the difference between electronics and electrical engineering? | ||
For this purpose, it is useful to take a closer look at the individual parts of the term " | For this purpose, it is useful to take a closer look at the individual parts of the term " | ||
- | The German wording for " | + | The German wording for " |
A __**circuit**__ is an arrangement of electrical or electronic components to form a functioning whole or an electric circuit. We already got to know the term circuit in [[electrical Engineering 1: | A __**circuit**__ is an arrangement of electrical or electronic components to form a functioning whole or an electric circuit. We already got to know the term circuit in [[electrical Engineering 1: | ||
- | __**Electronics**__ is derived from the word electrons. This " | + | __**Electronics**__ is derived from the word electrons. This " |
=== Is it Electronics? | === Is it Electronics? | ||
- | We will now examine the term electronics more detail using various examples. | + | We will now examine the term electronics |
- | First of all, a transformer will be considered. Is this an electrical or electronic component? In a transformer, | + | First of all, a transformer will be considered. Is this an electrical or electronic component? In a transformer, |
- | The second example is the so-called {{wp> | + | The second example is the so-called {{wp> |
- | The last example to be studied in the light of electronics and electrical engineering is the electron tube. An electron tube is a vacuum vessel, with several connections. Two of the connections lead internally to one electrode each, which face each other. These can be brought to a potential difference against each other and heated. This allows electrons to escape from the electrode and generate a current to the other electrode through the vacuum. A grid is placed between these two electrodes. If this is set to an opposite potential, the current flow can be stopped. Here, the grid potential can be used to change the current flow. The electron tube is already considered | + | The last example to be studied in the light of electronics and electrical engineering is the electron tube. An electron tube is a vacuum vessel, with several connections. Two of the connections lead internally to one electrode each, which faces each other. These can be brought to a potential difference against each other and heated. This allows electrons to escape from the electrode and generate a current to the other electrode through the vacuum. A grid is placed between these two electrodes. If this is set to an opposite potential, the current flow can be stopped. Here, the grid potential can be used to change the current flow. The electron tube is already considered an electronic component. Nowadays the electron tube has been replaced by semiconductor components. \\ \\ |
- | In this course we only deal with semiconductor electronic components and basically with silicon as semiconductor. | + | In this course, we only deal with semiconductor electronic components and basically with silicon as semiconductor. |
Zeile 41: | Zeile 41: | ||
- | ===== 1.1 Amplifier - a black box is going to be specified ===== | + | ===== 1.1 Amplifier - a Black Box is going to be specified ===== |
Before the amplifier is examined in more detail in the application, | Before the amplifier is examined in more detail in the application, | ||
Zeile 47: | Zeile 47: | ||
<panel type=" | <panel type=" | ||
<WRAP group>< | <WRAP group>< | ||
- | An amplifier is a system that uses a low power input signal to control a much higher power output signal. \\ \\ | + | An amplifier is a system that uses a low-power input signal to control a much higher-power output signal. \\ \\ |
The necessary energy is taken from the power supply! | The necessary energy is taken from the power supply! | ||
</ | </ | ||
Zeile 54: | Zeile 54: | ||
==== Characteristics ==== | ==== Characteristics ==== | ||
- | Mostly, when an amplifier is used, it is specifically a voltage amplifier. Accordingly, | + | Mostly, when an amplifier is used, it is specifically a voltage amplifier. Accordingly, |
< | < | ||
< | < | ||
</ | </ | ||
- | {{drawio> | + | {{drawio> |
</ | </ | ||
- | The symbol of the amplifier is a rectangle with an inserted triangle. The input terminals on the left side are marked $IN+$ and $IN-$. The output terminals on the right side are correspondingly labeled $OUT+$ and $OUT-$. The input voltage $U_I$ is applied between the input terminals and the output voltage $U_{O}$ is applied between the output terminals. | + | The symbol of the amplifier is a rectangle with an inserted triangle. The input terminals on the left side are marked $\rm IN+$ and $\rm IN-$. The output terminals on the right side are correspondingly labeled $\rm OUT+$ and $\rm OUT-$. The input voltage $U_\rm I$ is applied between the input terminals and the output voltage $U_{\rm O}$ is applied between the output terminals. |
The signal to be amplified comes from any source on the left-hand side. Often this can be seen as an ideal (voltage) source - i.e. with internal resistance. The amplified signal is fed to a load on the right-hand side. In the simplest case, this load is an ohmic resistor. | The signal to be amplified comes from any source on the left-hand side. Often this can be seen as an ideal (voltage) source - i.e. with internal resistance. The amplified signal is fed to a load on the right-hand side. In the simplest case, this load is an ohmic resistor. | ||
- | In <imgref pic001> a simulation of an ideal amplifier is shown. The input source specifies the voltage to be amplified. The amplifier with amplification factor 100 has the connections for input and output voltage drawn in. On the right side a resistor is provided as load; this can be varied via a switch. \\ \\ | + | In <imgref pic001> a simulation of an ideal amplifier is shown. The input source specifies the voltage to be amplified. The amplifier with an amplification factor |
~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
Zeile 77: | Zeile 77: | ||
- Ideally, no current flows into the amplifier on the input side. | - Ideally, no current flows into the amplifier on the input side. | ||
- The current on the output side depends on the connected load. If the load resistance is reduced with the help of the switch, the current increases. The amplifier thus tries to maintain the desired voltage. | - The current on the output side depends on the connected load. If the load resistance is reduced with the help of the switch, the current increases. The amplifier thus tries to maintain the desired voltage. | ||
- | - On the output side of the amplifier, the current can flow in either direction. \\ The amplifier adjusts the current so that the amplified voltage $U_A=\pm 2.5V$ can be measured at the output. | + | - On the output side of the amplifier, the current can flow in either direction. \\ The amplifier adjusts the current so that the amplified voltage $U_A=\pm 2.5~\rm V$ can be measured at the output. |
\\ | \\ | ||
Zeile 83: | Zeile 83: | ||
<panel type=" | <panel type=" | ||
{{tablelayout? | {{tablelayout? | ||
- | ^ Characteristic groups^ # ^ Characteristic (deutsch) | + | ^ Characteristic groups^ # |
- | | Ratios ^ 1 | Spannungsverstärkung $A_V$ | + | | Ratios |
- | | ::: ^ 2 | Stromverstärkung $A_C$ | + | | ::: ^ 2 | Stromverstärkung |
- | | ::: ^ 3 | Übertragungswiderstand $R_ü$ | + | | ::: ^ 3 | Übertragungswiderstand $R_{\rm ü}$ |
- | | ::: ^ 4 | Übertragungsleitwert (Steilheit) $G, S$ | Transmission | + | | ::: ^ 4 | Übertragungsleitwert (Steilheit) $G, S$ | Transfer |
- | | Input/ | + | | Input/ |
- | | ::: | + | | ::: ^ 6 | Ausgangswiderstand |
- | | Reverse gains ^ 7 | Spannungsrückwirkung $A_{rV}$ | Reverse Voltage Gain | $\large{A_{rV} =\frac{U_I}{U_O}}$ | | + | | Reverse gains ^ 7 | Spannungsrückwirkung $A_{\rm rV}$ | Reverse Voltage Gain |
- | | ::: | + | | ::: ^ 8 | Stromrückwirkung |
</ | </ | ||
</ | </ | ||
~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
- | The ratios of the input and output quantities of a black box are called **characteristics**. A well-known parameter is, for example, the efficiency $\eta = \frac{P_O}{P_I}$. In the case of an amplifier, only the voltages and currents are considered as input and output quantities. Various amplifier parameters are shown in the table. \\ | + | The ratios of the input and output quantities of a black box are called **characteristics**. A well-known parameter is, for example, the efficiency $\eta = \frac{P_{\rm O}}{P_{\rm I}}$. In the case of an amplifier, only the voltages and currents are considered as input and output quantities. Various amplifier parameters are shown in the table. \\ |
- | Different transmission ratios result, depending on the desired input variable and the output variable, which is to be controlled. It is important that the transmission resistance $R_T$ and the transfer conductance $S$ do not correspond to any electrical component, since current and voltage are not measured at the same terminals. | + | Different transmission ratios result, depending on the desired input variable and the output variable, which is to be controlled. It is important that the transmission resistance $R_\rm T$ and the transfer conductance $S$ do not correspond to any electrical component, since current and voltage are not measured at the same terminals. |
- | When current and voltage at the same "side "are put into relation, the input resistance $\boldsymbol{R_I}$ and the output resistance $R_O$ result. From [[: | + | When current and voltage at the same "side "are put into relation, the input resistance $\boldsymbol{R_{\rm I}}$ and the output resistance $R_\rm O$ result. From [[: |
- | However, for output resistance $\boldsymbol{R_O}$ (in the amplifier), the arrows of $U_O$ and $I_O$ are antiparallel. Therefore the fraction is a negative value. For getting a resitance | + | However, for output resistance $\boldsymbol{R_{\rm O}}$ (in the amplifier), the arrows of $U_\rm O$ and $I_\rm O$ are antiparallel. Therefore the fraction is a negative value. For getting a resistance |
- | The most important characteristics of the voltage amplifier are the voltage gain $A_V$, as well as the input and output resistance $R_I$ and $R_O$. | + | The most important characteristics of the voltage amplifier are the voltage gain $A_\rm V$, as well as the input and output resistance $R_\rm I$ and $R_\rm O$. |
~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
- | ==== Equivalent | + | ==== Equivalent |
< | < | ||
< | < | ||
</ | </ | ||
- | {{drawio> | + | {{drawio> |
</ | </ | ||
- | After the view on the characteristics, | + | After the view on the characteristics, |
~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
Zeile 120: | Zeile 120: | ||
</ | </ | ||
- | The simulation shows a **(simulated) real amplifier**. The input source has a high internal resistance. This means it has a high impedance and can only supply a small amount of current. The amplifier with a gain of 100 has - beside | + | The simulation shows a **(simulated) real amplifier**. The input source has a high internal resistance. This means it has a high impedance and can only supply a small amount of current. The amplifier with a gain of 100 has - besides |
| | ||
Zeile 127: | Zeile 127: | ||
- The current on the output side depends on the connected load. If the load resistance is reduced with the help of the switch, the current increases. The amplifier thus tries to maintain the desired voltage. | - The current on the output side depends on the connected load. If the load resistance is reduced with the help of the switch, the current increases. The amplifier thus tries to maintain the desired voltage. | ||
- The amplifier can output current as well as absorb current. \\ The current on the output side flows in and out of the amplifier through the supply voltage connections. | - The amplifier can output current as well as absorb current. \\ The current on the output side flows in and out of the amplifier through the supply voltage connections. | ||
- | - The simulation is based on a real amplifier. This has a small deviation from the expected value $U_O=\pm 2.5V$ at the output voltage. Part of the deviation will be described later in this chapter. | + | - The simulation is based on a real amplifier. This has a small deviation from the expected value $U_{\rm O}=\pm 2.5~\rm V$ at the output voltage. Part of the deviation will be described later in this chapter. |
~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
Zeile 137: | Zeile 137: | ||
<panel type=" | <panel type=" | ||
{{tablelayout? | {{tablelayout? | ||
- | ^ # ^ Amplifier | + | ^ # ^ Amplifier |
- | ^ 1 | voltage amplifier | + | ^ 1 | voltage amplifier |
- | ^ 2 | current amplifier | + | ^ 2 | current amplifier |
- | ^ 3 | current-to-voltage converter | {{drawio> | + | ^ 3 | current-to-voltage converter | {{drawio> |
- | ^ 4 | voltage-to-current converter | {{drawio> | + | ^ 4 | voltage-to-current converter | {{drawio> |
</ | </ | ||
</ | </ | ||
- | As a symbol in {{wp> | + | As a symbol in {{wp> |
- | Now the **input resistance** $\boldsymbol{R_I}$ and **output resistance** $\boldsymbol{R_O}$ for ideal voltage amplifiers shall be considered in more detail. | + | Now the **input resistance** $\boldsymbol{R_\rm I}$ and **output resistance** $\boldsymbol{R_\rm O}$ for ideal voltage amplifiers shall be considered in more detail. |
- | If a voltage is the input, the input resistance should load the source as little as possible so that the voltage to be measured does not drop (cf. <imgref pic2>). This can also be easily checked in the simulation of the real amplifier (see above). If the resistance of the load is increased there (double-click), | + | If a voltage is the input, the input resistance should load the source as little as possible so that the voltage to be measured does not drop (cf. <imgref pic2>). This can also be easily checked in the simulation of the real amplifier (see above). If the resistance of the load is increased there (double-click), |
- | A similar consideration can be made for the **output resistance** $\boldsymbol{R_O}$. If a voltage is the output parameter, the output resistor must be dimensioned in such a way that the voltage at the load does not drop at the output either. The output resistance should be as small as possible so that the voltage | + | A similar consideration can be made for the **output resistance** $\boldsymbol{R_\rm O}$. If a voltage is the output parameter, the output resistor must be dimensioned in such a way that the voltage at the load does not drop at the output either. The output resistance should be as small as possible so that the voltage |
~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
Zeile 155: | Zeile 155: | ||
< | < | ||
</ | </ | ||
- | {{drawio> | + | {{drawio> |
</ | </ | ||
- | Now, if the **input resistances** $\boldsymbol{R_I}$ **and output resistances** $\boldsymbol{R_O}$ **for __ideal current amplifiers__** are considered, a different view of the amplifier is favorable. In the <imgref pic3> the same amplifier considered so far can be seen. However, in this case all real voltage sources are replaced by real current sources. This transformation has already been described in [[Electrical Engineering 1:start]]. Depending on the considered electrical quantity, one or the other real source can be advantageous. \\ The input and output resistance of the current amplifier shall be considered with this knowledge. On the input side, most of the input current $I_I$ should flow into the amplifier. The input resistance $R_I$ must accordingly tend towards zero. The maximum current should also flow out of the amplifier at the amplifier output. Here, the output resistance $R_O$ must accordingly tend towards infinity, so that the lowest possible current flows through it. | + | Now, if the **input resistances** $\boldsymbol{R_\rm I}$ **and output resistances** $\boldsymbol{R_\rm O}$ **for __ideal current amplifiers__** are considered, a different view of the amplifier is favorable. In the <imgref pic3> the same amplifier considered so far can be seen. However, in this case, all real voltage sources are replaced by real current sources. This transformation has already been described in [[Electrical Engineering 1:start]]. Depending on the considered electrical quantity, one or the other real source can be advantageous. \\ The input and output resistance of the current amplifier shall be considered with this knowledge. On the input side, most of the input current $I_\rm I$ should flow into the amplifier. The input resistance $R_\rm I$ must accordingly tend towards zero. The maximum current should also flow out of the amplifier at the amplifier output. Here, the output resistance $R_\rm O$ must accordingly tend towards infinity so that the lowest possible current flows through it. |
The following applies to **__current-voltage and voltage-current converters__**: | The following applies to **__current-voltage and voltage-current converters__**: | ||
Zeile 168: | Zeile 168: | ||
< | < | ||
- | < | + | < |
</ | </ | ||
- | {{drawio> | + | {{drawio> |
</ | </ | ||
- | One of the fundamental principles of control engineering, | + | One of the fundamental principles of control engineering, |
- | In addition, there is another tool for control engineering, | + | In addition, there is another tool for control engineering, |
- | In contrast to this is the block diagram. This shows individual blocks which link a cause with an effect. In general, no reaction of the effect on the cause is assumed. Causes and effects can be voltages or currents, which are then written on the respective connecting arrow. The block diagram does not claim to conserve energy or charge, but serves to provide an overview of the effects and interrelationships. Thus Kirchhoff' | + | In contrast to this is the block diagram. This shows individual blocks which link a cause with an effect. In general, no reaction of the effect on the cause is assumed. Causes and effects can be voltages or currents, which are then written on the respective connecting arrow. The block diagram does not claim to conserve energy or charge but serves to provide an overview of the effects and interrelationships. Thus Kirchhoff' |
- | <imgref pic4> shows a block diagram of a feedback amplifier consisting of an ideal voltage amplifier with gain $A_D$ drawn in the center. The output voltage $U_O$, reduced by the factor $k$, is fed back via a feedback element. The circle symbol with the arithmetic symbols (in the block diagram on the left) shows how the incoming values must be offset against each other. The value $k \cdot U_O$ is thus subtracted from the input value $U_I$ in the indicated block diagram. \\ \\ | + | <imgref pic4> shows a block diagram of a feedback amplifier consisting of an ideal voltage amplifier with gain $A_\rm D$ drawn in the center. The output voltage $U_\rm O$, reduced by the factor $k$, is fed back via a feedback element. The circle symbol with the arithmetic symbols (in the block diagram on the left) shows how the incoming values must be offset against each other. The value $k \cdot U_\rm O$ is thus subtracted from the input value $U_\rm I$ in the indicated block diagram. \\ \\ |
- | The advantage of a real amplifier in negative feedback is that the gain $A_V$ of the whole system depends only negligibly on the gain factor $A_D$ of the real amplifier, if $A_D$ is very large (see also task 1.3.2). In this case, the gain $A_V=\frac{1}{k}$. To avoid oscillation of the whole system, the amplifier must contain a delay element. This is present in the real amplifier in such a way that the output voltage $U_O$ cannot change infinitely fast. [(Note2> | + | The advantage of a real amplifier in negative feedback is that the gain $A_\rm V$ of the whole system depends only negligibly on the gain factor $A_\rm D$ of the real amplifier if $A_\rm D$ is very large (see also task 1.3.2). In this case, the gain $ A_{\rm V}=\frac {1}{k}$. To avoid oscillation of the whole system, the amplifier must contain a delay element. This is present in the real amplifier in such a way that the output voltage $U_\rm O$ cannot change infinitely fast. [(Note2> |
- | + | ||
<WRAP column 80%> | <WRAP column 80%> | ||
<panel type=" | <panel type=" | ||
Zeile 184: | Zeile 184: | ||
**__Feedback__** (German: **__Rückkopplung__**) refers to the return of part of the output signal of an amplifier. \\ | **__Feedback__** (German: **__Rückkopplung__**) refers to the return of part of the output signal of an amplifier. \\ | ||
- | With **__positive__** (German: **__Mitkopplung__**) feedback, the part of the output signal with positive sign is fed back. | + | With **__positive__** (German: **__Mitkopplung__**) feedback, the part of the output signal with a positive sign is fed back. |
The output value is therefore always increased by the input value. | The output value is therefore always increased by the input value. | ||
\\ \\ | \\ \\ | ||
Zeile 197: | Zeile 197: | ||
<panel type=" | <panel type=" | ||
<WRAP group>< | <WRAP group>< | ||
- | The **differential gain** or **open-loop gain** $\boldsymbol{A_D}$ (German: Differenzverstärkung) refers only to input and output voltage of the inner amplifier: $A_D=\frac{U_O}{U_D}$. | + | The **differential gain** or **open-loop gain** $\boldsymbol{A_\rm D}$ (German: Differenzverstärkung) refers only to the input and output voltage of the inner amplifier: $A_{\rm D}=\frac{U_\rm O}{U_\rm D}$. |
This acts only without external feedback. It is also called open-loop gain. \\ \\ | This acts only without external feedback. It is also called open-loop gain. \\ \\ | ||
- | The **voltage gain** $\boldsymbol{A_V}$ refers to input and output voltage of the whole circuit with feedback: $A_V=\frac{U_O}{U_I}$. \\ It is also called closed-loop gain. \\ \\ | + | The **voltage gain** $\boldsymbol{A_\rm V}$ refers to the input and output voltage of the whole circuit with feedback: $A_{\rm V}=\frac{U_\rm O}{U_\rm I}$. \\ It is also called closed-loop gain. \\ \\ |
</ | </ | ||
</ | </ | ||
Zeile 212: | Zeile 212: | ||
{{page> | {{page> | ||
- | ====== Learning | + | ====== Learning |
- | === for your self-study === | + | === for your Self-Study === |
* What is the definition of an amplifier? | * What is the definition of an amplifier? | ||
* Explain with an example what is the essence of an amplifier. | * Explain with an example what is the essence of an amplifier. | ||
Zeile 221: | Zeile 221: | ||
* When is it called positive feedback and when is it called negative feedback? | * When is it called positive feedback and when is it called negative feedback? | ||
* Explain the principle of negative feedback. | * Explain the principle of negative feedback. | ||
- | * What is the difference between voltage gain and differential gain? Briefly describe the difference between $A_V$ and $A_D$. | + | * What is the difference between voltage gain and differential gain? Briefly describe the difference between $A_\rm V$ and $A_\rm D$. |
- | * How does $A_D$ affect the output voltage $U_O$ when there is no feedback in an op-amp circuit? | + | * How does $A_\rm D$ affect the output voltage $U_\rm O$ when there is no feedback in an op-amp circuit? |
- | * What is the effect of $A_D$ on the output voltage $U_O$ when feedback is present in an op-amp circuit and $A_D$ is increased from 100,000 to 200,000? | + | * What is the effect of $A_\rm D$ on the output voltage $U_\rm O$ when feedback is present in an op-amp circuit and $A_\rm D$ is increased from $100'000$ to $200'000$? |
* At what value for k does the feedback become maximum? | * At what value for k does the feedback become maximum? | ||
- | * What values can k take for a passively | + | * What values can k take for a passive |
* What effect does k have on the amplifier? | * What effect does k have on the amplifier? | ||
* What happens if you feed back the entire output voltage? | * What happens if you feed back the entire output voltage? | ||
- | === with answers | + | === with Answers |
<WRAP group> | <WRAP group> | ||
<WRAP column half> | <WRAP column half> | ||
- | <panel type=" | + | < |
- | <quizlib id="quiz1" rightanswers=" | + | |
- | < | + | |
- | $R_O = \Delta U_I / \Delta I_O$| | + | |
- | $R_O = U_I / I_O$| | + | |
- | $R_O = \Delta U_O / \Delta I_O$| | + | |
- | $R_O = -\Delta U_O / \Delta I_O$| | + | |
- | $R_O = U_O / I_O$ | + | |
- | </ | + | |
- | <panel type=" | ||
- | <quizlib id=" | ||
- | < | ||
- | $R_I → 0$, $R_O → ∞$| | ||
- | $R_I → 0$, $R_O → 0$| | ||
- | $R_I → ∞$, $R_O → 0$| | ||
- | $R_I → ∞$, $R_O → ∞$ | ||
- | </ | ||
- | <panel type=" | + | {{page> |
+ | {{page> | ||
+ | |||
+ | <panel type=" | ||
<quizlib id=" | <quizlib id=" | ||
- | < | + | < |
Current-to-voltage converter| | Current-to-voltage converter| | ||
Current amplifier| | Current amplifier| | ||
Zeile 264: | Zeile 251: | ||
</ | </ | ||
- | <panel type=" | + | <panel type=" |
<quizlib id=" | <quizlib id=" | ||
< | < | ||
Cannot be measured using a resistance meter| | Cannot be measured using a resistance meter| | ||
Can be used for voltage dividers| | Can be used for voltage dividers| | ||
- | Is given by ${U_I} \over {I_O}$, with input voltage $U_I$ and output current $I_O$| | + | Is given by ${U_\rm I} \over {I_\rm O}$, with input voltage $U_\rm I$ and output current $I_\rm O$| |
represents the gain | represents the gain | ||
</ | </ | ||
- | <panel type=" | + | <panel type=" |
<quizlib id=" | <quizlib id=" | ||
< | < | ||
... needs an additional power supply for the amplification.| | ... needs an additional power supply for the amplification.| | ||
... can only be built with positive feedback. | | ... can only be built with positive feedback. | | ||
- | ... controls by an input circuit with high power an output with small power.| | + | ... controls by an input circuit with high power output with small power.| |
... has to include a voltage divider | ... has to include a voltage divider | ||
</ | </ | ||
</ | </ |