13.2.1 Understanding bipolar junction transistors (BJTs)

• What is a Bipolar Junction Transistor (BJT)?

  A transistor using electrons and holes
• The base of a BJT controls the current flow between the collector and the emitter
• An NPN BJT requires positive voltage at the base to conduct.


  True
• What is the function of the emitter in a BJT?

  Emits charge carriers
• Holes are the primary charge carriers in a PNP BJT.


  True
• NPN BJTs require a positive voltage at the base to conduct.


  True
• BJTs amplify current using a small base current to control a larger collector current.

  True
• What is the typical range of current gain for NPN BJTs?

  50-500
• Common emitter, common base, and common collector are the three main configurations of BJTs.

  True
• The common base configuration is often used for high-frequency amplifiers
• Match the BJT type with its structure:

  NPN ↔️ n-p-n

  PNP ↔️ p-n-p
• PNP BJTs require a negative voltage at the base
• The base current in a PNP BJT is negative
• In PNP BJTs, the collector current flows from collector to emitter.


  True
• In both NPN and PNP BJTs, the current gain (β) typically ranges from 50 to 500
• Match the BJT component with its function:

  Emitter ↔️ Emits charge carriers into the base

  Base ↔️ Controls the current flow

  Collector ↔️ Collects the charge carriers
• BJTs are classified into NPN and PNP types based on semiconductor layer arrangement.


  True
• What type of voltage is required at the base of a PNP BJT for conduction?

  Negative
• What is the structure of an NPN BJT?

  n-type, p-type, n-type
• In an NPN BJT, electrons flow from the emitter to the collector.


  True
• In a PNP BJT, holes flow from the emitter to the collector.


  True
• A PNP BJT requires a negative voltage at the base to conduct.
• A BJT can amplify current using a small base current to control a larger collector current.
• Match the feature with the correct BJT type:

  Positive Base Current ↔️ NPN

  Negative Base Current ↔️ PNP
• The common collector configuration has low voltage gain but high current gain.


  True
• What is the relationship between the input base current and the output collector current in BJTs described by?

  Current gain
• What is the typical range of current gain for NPN BJTs?

  50-500
• Match the type of BJT with the direction of collector current flow:

  NPN BJT ↔️ Emitter to collector

  PNP BJT ↔️ Collector to emitter
• The three main BJT biasing configurations are common emitter, common base, and common collector
• In which application is the common emitter configuration often used?

  Switching circuits
• The base of a BJT controls the current flow between the collector and emitter.


  True
• What is the formula for current gain in BJTs?

  β = IC / IB
• What type of voltage is required at the base of a PNP BJT to conduct?

  Negative
• Electrons are the charge carriers in a PNP BJT.

  False
• What type of base current is required in an NPN BJT for current amplification?

  Positive
• Match the BJT configuration with its key feature:

  Common Emitter ↔️ High voltage and current gain

  Common Base ↔️ High voltage gain, low current gain

  Common Collector ↔️ High current gain, low voltage gain
• The common collector configuration provides high current gain and low output impedance.

  True
• The current gain (β) for both NPN and PNP BJTs is typically in the range of 50-500.


  True
• A BJT consists of three terminals: Base, Collector, and Emitter
• The structure of a BJT involves two p-n junctions.


  True