Examkin

Transistors

31 soru

Tüm türler31Çoktan seçmeli17Doğru / Yanlış8Eşleştirme6
Soru 21Soru →

In a bipolar junction transistor circuit, a small input current supplied to the base terminal is used to control a significantly larger current flowing between which two terminals?

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Cevap: The collector and the emitter

Cevap

The collector and the emitter
A bipolar junction transistor functions as a current-controlled amplifier or switch. A relatively small base current (IBI_B) modulates a significantly larger current (ICI_C) flowing across the main conduction channel between the collector and the emitter.

Adım Adım Çözüm

1
Identify the component type and its standard terminal leads.
A bipolar junction transistor (BJT) consists of three active terminals: the base (B), collector (C), and emitter (E).
Terminal designations distinguish BJTs from other semiconductor devices such as FETs or diodes.
2
Determine the functional relationship between the input control lead and the main output conduction channel.
A small current entering the base terminal forward-biases the base-emitter junction, permitting a much larger current (proportional by the gain factor beta) to flow between the collector and the emitter.
BJTs operate as current-controlled devices where the base-emitter circuit governs the primary collector-to-emitter current channel.

Anahtar Kavram

Bipolar Junction Transistor (BJT) terminal roles and current amplification principle
Tahmini Süre:45s
Soru 22Soru →

Match each fundamental transistor operating concept on the left with its correct electrical definition on the right.

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Öğeler

Amplification
Switching
Biasing

Eşleşmeler

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Cevap

Amplification matches 'Using a small varying input signal to control a larger output signal'; Switching matches 'Alternating between full conduction and complete cutoff to control power to a load'; Biasing matches 'Applying preset DC voltages to establish a stable quiescent operating point'.
Each concept pairs directly with its fundamental role in electronics: Amplification scales a small input variation into a larger output signal; Switching toggles between full conduction and total cutoff to activate or deactivate loads; Biasing establishes the necessary static direct-current voltages across terminals for stable circuit operation.

Adım Adım Çözüm

1
Identify the definition of signal amplification in solid-state electronics.
Amplification corresponds to increasing signal strength by using small input fluctuations to modulate larger power supplies.
In linear active mode, transistors amplify weak audio, radio, or sensor signals.
2
Identify the functional definition of electronic switching.
Switching corresponds to toggling between saturation (closed/on) and cutoff (open/off).
Digital and power control circuits use transistors as high-speed electronic switches without moving parts.
3
Identify the purpose and definition of transistor biasing.
Biasing corresponds to setting baseline DC voltage levels at the terminals.
Proper DC bias ensures the semiconductor junctions maintain the required operational state (forward-biased base-emitter, reverse-biased base-collector).

Anahtar Kavram

Core operational principles and functional modes of transistors
Tahmini Süre:45s
Soru 23Soru →

An electronics technician is analyzing solid-state circuit topologies for an audio and radio frequency transceiver. Match each transistor circuit configuration or operational mode with its defining electrical characteristic.

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Öğeler

Common Emitter Configuration
Common Collector (Emitter Follower) Configuration
Common Base Configuration
Transistor Switch Mode

Eşleşmeler

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Cevap

Common Emitter Configuration matches with significant voltage/current gain and 180∘180^\circ phase inversion; Common Collector Configuration matches with high input impedance, low output impedance, and near-unity voltage gain; Common Base Configuration matches with low input impedance, high voltage gain, and no phase inversion for high-frequency RF; Transistor Switch Mode matches with alternating between cutoff and saturation to control load power.
Each transistor configuration serves a specific role determined by which terminal is common to both input and output: Common Emitter is the primary inverting voltage/current amplifier; Common Collector serves as a non-inverting impedance buffer with unity voltage gain; Common Base provides low input impedance and high-frequency stability without phase shift; and Switch Mode drives the transistor between saturation and cutoff for binary power control.

Adım Adım Çözüm

1
Identify the phase relationship and gain characteristics of the Common Emitter amplifier.
The Common Emitter takes input at the base and extracts output at the collector, yielding voltage gain, current gain, and a 180∘180^\circ phase inversion.
This is the signature standard amplifier configuration in bipolar transistor circuitry.
2
Analyze the impedance transformation and voltage gain of the Common Collector configuration.
The Common Collector takes input at the base and extracts output at the emitter, yielding a voltage gain of slightly less than 1 with high input impedance and low output impedance.
This configuration acts as a buffer or impedance matching stage, commonly termed an emitter follower.
3
Identify the high-frequency and impedance properties of the Common Base configuration.
The Common Base takes input at the emitter and output at the collector with the base grounded for AC signals, offering low input impedance and no signal inversion.
The grounded base shields input from output, mitigating the Miller effect in RF circuits.
4
Distinguish linear amplification from digital switching operation.
Switching mode avoids the active linear region and toggles strictly between cutoff (IC=0I_C = 0) and saturation (VCE≈0.2 VV_{CE} \approx 0.2\text{ V}).
Digital control and relay driving rely on binary on/off states rather than linear proportional amplification.

Anahtar Kavram

Transistor Circuit Configurations and Operating Modes
Tahmini Süre:1m 0s
Soru 24Soru →

In a field-effect transistor (FET), which terminal serves as the control element that regulates the current passing between the source and the drain?

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Cevap: Gate

Cevap

Gate
In a field-effect transistor (FET), the gate terminal applies an electric field that alters the conductivity of the semiconductor channel, thereby regulating the flow of current between the source and the drain.

Adım Adım Çözüm

1
Identify the transistor family specified in the question.
The device is a field-effect transistor (FET), which utilizes Gate, Source, and Drain terminals.
Field-effect transistors use different terminal designations and operational principles compared to bipolar junction transistors.
2
Determine the functional role of each FET terminal.
Current enters at the source and leaves through the drain, while voltage applied to the gate controls channel conductivity.
The gate terminal acts as the primary control electrode that modulates current flow between the source and drain.

Anahtar Kavram

Field-Effect Transistor (FET) Terminal Designations and Roles
Tahmini Süre:45s
Soru 25Soru →

While standard bipolar junction transistors (BJTs) operate as current-controlled components, field-effect transistors (FETs) are commonly used in high-impedance input stages. What is the primary operating mechanism of a field-effect transistor?

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Cevap: Regulating current between the source and drain using an electric field established by a gate voltage

Cevap

Regulating current between the source and drain using an electric field established by a gate voltage
A field-effect transistor (FET) controls the flow of electrical charge carriers between the source and drain terminals by varying the strength of an electrostatic field within the semiconductor channel. This field is established by applying a voltage to the gate terminal, allowing the device to modulate conductivity with almost zero input gate current.

Adım Adım Çözüm

1
Identify the fundamental category and terminals of a Field-Effect Transistor (FET)
FETs have three primary terminals: Gate, Drain, and Source.
Recognizing terminal designations separates FET functionality from BJT terminals (Base, Collector, Emitter).
2
Determine the control mechanism of a FET
An electric field created by voltage applied to the gate controls the conductive channel between the source and drain.
FETs are voltage-controlled solid-state devices that draw negligible gate current due to extremely high input resistance.

Anahtar Kavram

Field-Effect Transistor (FET) Voltage-Controlled Operation
Tahmini Süre:1m 0s
Soru 26Soru →

For a bipolar junction transistor (BJT) to operate in the active amplification mode, the base-emitter junction must be forward-biased while the base-collector junction is reverse-biased.

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Cevap: True

Cevap

True. Operating a bipolar junction transistor in the active amplification region requires a forward-biased base-emitter junction and a reverse-biased base-collector junction.
The statement is correct because linear amplification in a bipolar junction transistor strictly requires the input base-emitter diode junction to be forward-biased to initiate current flow, and the output collector-base junction to be reverse-biased to sweep and gather charge carriers into the collector circuit.

Adım Adım Çözüm

1
Identify the specified operating state of the transistor
The transistor is designated to operate in active (linear) amplification mode.
A transistor exhibits distinct junction biasing configurations depending on whether it functions in cutoff, saturation, or active mode.
2
Determine the required bias across the base-emitter junction
The base-emitter junction must be forward-biased.
Forward-biasing this junction overcomes the internal barrier potential (approximately 0.7 V for silicon) and injects carriers into the base.
3
Determine the required bias across the base-collector junction
The base-collector junction must be reverse-biased.
Reverse-biasing this junction establishes a wide depletion region with an electric field that sweeps the injected carriers into the collector.
4
Evaluate the accuracy of the statement
The statement correctly describes both required junction conditions.
The combination of a forward-biased base-emitter junction and a reverse-biased base-collector junction precisely defines active region operation.

Anahtar Kavram

Bipolar Junction Transistor Biasing and Operating Modes
Tahmini Süre:45s
Soru 27Soru →

In a bipolar junction transistor (BJT) amplifier circuit operating in its active region, a base current (IBI_B) of 2 mA2\text{ mA} is applied. If the transistor has a common-emitter DC current gain (β\beta or hFEh_{FE}) of 5050, what is the resulting collector current (ICI_C) flowing through the transistor?

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Cevap: 100 mA100\text{ mA}

Cevap

The collector current (ICI_C) is 100 mA100\text{ mA}.
In the active region of a bipolar junction transistor, the collector current is directly proportional to the base current by the factor of DC current gain: IC=β×IBI_C = \beta \times I_B. Multiplying the base current of 2 mA2\text{ mA} by the gain of 5050 yields 100 mA100\text{ mA}.

Adım Adım Çözüm

1
Identify the given values and formula for transistor DC current gain in the active region.
Given IB=2 mAI_B = 2\text{ mA} and β=50\beta = 50. The governing formula is IC=β×IBI_C = \beta \times I_B.
Current gain (β\beta) represents the amplification factor between the controlling base current and the controlled collector current.
2
Substitute the measured base current and gain into the current equation.
IC=50×2 mA=100 mAI_C = 50 \times 2\text{ mA} = 100\text{ mA}.
Calculating the product gives the total current flowing through the collector terminal.

Anahtar Kavram

Bipolar Junction Transistor DC Current Gain (β\beta or hFEh_{FE})
Tahmini Süre:1m 0s
Soru 28Soru →

Electronic systems utilize various solid-state semiconductor transistors tailored for specific switching, amplification, and sensing applications. Match each transistor type to its defining operating principle and physical characteristic.

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Öğeler

Bipolar Junction Transistor (BJT)
Junction Field-Effect Transistor (JFET)
Metal-Oxide-Semiconductor FET (MOSFET)
Phototransistor

Eşleşmeler

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Cevap

Bipolar Junction Transistor (BJT) pairs with the current-controlled device using both electron and hole carriers; Junction Field-Effect Transistor (JFET) pairs with the voltage-controlled device using a reverse-biased PN junction; Metal-Oxide-Semiconductor FET (MOSFET) pairs with the insulated-gate component featuring high input impedance and an oxide dielectric; Phototransistor pairs with the optoelectronic component converting incident light into amplified collector current.
Each semiconductor device corresponds uniquely to its operating physics: BJTs are bipolar current-controlled devices; JFETs utilize reverse-biased PN junctions for channel modulation; MOSFETs employ an insulated dielectric gate for field-effect control; and phototransistors utilize optical stimulation to generate base-region carriers.

Adım Adım Çözüm

1
Identify the carrier conduction and control mechanism of the BJT
The BJT is a current-controlled bipolar device relying on both majority and minority carriers (electrons and holes).
The term bipolar explicitly indicates the participation of both carrier polarities, controlled by base current.
2
Differentiate between the field-effect transistor junction types (JFET vs. MOSFET)
The JFET relies on a direct reverse-biased PN gate junction, while the MOSFET incorporates an insulated oxide layer that eliminates DC gate current entirely.
The metal-oxide insulator in a MOSFET provides near-infinite input impedance compared to the reverse-biased PN junction of a JFET.
3
Distinguish the optoelectronic sensor category (Phototransistor)
The phototransistor operates by replacing or augmenting electrical base current with photon-generated charge carriers.
Light striking the transparent casing generates electron-hole pairs at the junction to initiate conduction.

Anahtar Kavram

Classification, control mechanisms, and structural properties of major transistor families
Tahmini Süre:1m 0s
Soru 29Soru →

An electronics technician is testing a bipolar junction transistor (BJT) configured as an electronic switch. When the base receives sufficient input voltage and current to drive the transistor into full conduction with minimum resistance between the collector and emitter, in which operating region is the transistor functioning?

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Cevap: Saturation region

Cevap

Saturation region
When a bipolar junction transistor is driven with sufficient base current to achieve maximum conduction, it operates in the saturation region. In saturation, both internal PN junctions are forward-biased, reducing the collector-to-emitter voltage (VCEV_{CE}) to a fraction of a volt (typically around 0.2 V0.2\text{ V}), effectively behaving like a closed mechanical switch.

Adım Adım Çözüm

1
Identify the circuit role and desired state of the transistor
The transistor operates as an electronic switch driven into full conduction (fully ON).
Transistors in switching circuits toggle between two primary binary states: fully OFF and fully ON.
2
Relate the fully ON switching condition to the characteristic BJT operating regions
Full conduction with minimal collector-to-emitter voltage drop occurs in the saturation region.
When both the base-emitter and base-collector junctions become forward-biased due to sufficient base drive, the transistor enters saturation, maximizing current flow through the load.

Anahtar Kavram

BJT Operating Regions and Switching States
Tahmini Süre:1m 0s
Soru 30Soru →

In standard electronic schematic symbols for bipolar junction transistors (BJTs), the arrow is located on the emitter terminal and points outward away from the base for an NPN transistor, indicating the direction of conventional current flow.

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Cevap: True

Cevap

True
The statement is true because electronic schematic standards place the directional arrow exclusively on the emitter lead. For an NPN transistor, this arrow points outward (away from the base), which reflects the direction of conventional current flow across the forward-biased base-emitter junction.

Adım Adım Çözüm

1
Identify the specific terminal that carries the directional arrow on a BJT schematic symbol.
The arrow is always placed on the emitter terminal, distinguishing it from the collector and base leads.
Standard electronic schematic conventions designate the emitter lead with an arrow to define transistor polarity and terminal identity.
2
Determine the orientation of the arrow for an NPN transistor configuration.
In an NPN transistor, the arrow points outward, away from the base.
The arrow represents the direction of forward-biased conventional current flow, moving from the P-type base material out through the N-type emitter material.
3
Evaluate the accuracy of the full statement.
The statement correctly identifies both the terminal location (emitter) and the outward direction for an NPN transistor.
Both structural elements conform exactly to standard electrical schematic rules.

Anahtar Kavram

BJT schematic symbol identification and terminal arrow direction
Tahmini Süre:45s
Soru 31Soru →

A technician is configuring a PNP bipolar junction transistor to operate as a switch. To forward-bias the base-emitter junction and turn the transistor ON, what electrical condition must be established at the base terminal relative to the emitter?

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Cevap: The base voltage must be lower (more negative) than the emitter voltage.

Cevap

The base voltage must be lower (more negative) than the emitter voltage.
For a PNP bipolar junction transistor to turn ON, its base-emitter P-N junction must be forward-biased. Because the emitter is P-type semiconductor material and the base is N-type material, the base terminal must be held at a lower (more negative) electrical potential than the emitter terminal (typically by at least 0.7 V0.7\text{ V} in standard silicon transistors).

Adım Adım Çözüm

1
Identify the transistor polarity and internal semiconductor structure.
A PNP transistor consists of an N-type base sandwiched between a P-type emitter and a P-type collector.
Understanding layer material types determines the required voltage polarities across the junctions.
2
Determine the biasing requirement for the base-emitter junction to allow conduction.
To forward-bias a P-N junction (P-type emitter to N-type base), the P-type region must be more positive than the N-type region.
Current can only flow across a forward-biased junction when the appropriate potential difference overcomes the barrier voltage (typically 0.7 V0.7\text{ V} for silicon).
3
Formulate the necessary base terminal condition relative to the emitter.
The base voltage must be pulled lower (more negative) relative to the emitter voltage, allowing conventional current to flow out of the base.
This establishes forward bias at the base-emitter junction, switching the PNP transistor ON.

Anahtar Kavram

PNP Transistor Biasing and Conduction Principles
Tahmini Süre:1m 0s
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