13.2.1 Understanding bipolar junction transistors (BJTs)

• What are the two types of bipolar junction transistors (BJTs)?

  NPN and PNP
• What are the primary charge carriers in a PNP BJT?

  Holes
• In an NPN BJT, the Collector is the terminal where current flows into the device.


  True
• Both PNP and NPN BJTs consist of three semiconductor layers
• Order the current flow in a PNP BJT when a small current is drawn from the Base.

  1️⃣ Emitter

  2️⃣ Collector
• What is the role of the Base in a BJT?

  Controls current flow
• In an NPN BJT, current flows from the Collector to the Emitter when a small current is applied to the Base.

  True
• In a PNP BJT, current flows from the Emitter to the Collector.
• What is the primary difference between PNP and NPN BJTs?

  Doping configurations
• In an NPN BJT, current flows from the Collector to the Emitter.
• Why is understanding the structural differences between PNP and NPN BJTs crucial?

  Effective circuit applications
• In an NPN BJT, current flows from the Collector to the Emitter when a small current is applied to the Base.


  True
• The Base terminal in a BJT controls the current flow between the Collector and the Emitter
• What are BJTs commonly used for in circuits?

  Amplifying and switching
• Match the BJT type with its characteristic:

  PNP BJT ↔️ p-n-p structure

  NPN BJT ↔️ n-p-n structure
• In an NPN BJT, electrons are the primary charge carriers.


  True
• In a PNP BJT, the layers are configured as p-type, n-type, p-type
• What type of BJT has its layers configured as p-type, n-type, p-type?

  PNP BJT
• In a PNP BJT, holes are the primary charge carriers.


  True
• Match the feature with the correct type of BJT:

  PNP BJT ↔️ p-n-p

  NPN BJT ↔️ n-p-n
• Electrons are the primary charge carriers in NPN BJTs.


  True
• BJTs amplify current by controlling the current between the Collector and Emitter with a small Base current.
• What are the three main regions of operation for BJTs?

  Cutoff, active, saturation
• The active region of a BJT allows it to amplify signals.


  True
• What are the two types of BJTs based on their structure?

  NPN and PNP
• Match the feature with the correct type of BJT:

  NPN BJT ↔️ Electron carriers

  PNP BJT ↔️ Hole carriers
• In an NPN BJT, current flows from the Collector to the Emitter when a small current is applied to the Base.


  True
• PNP and NPN BJTs consist of three semiconductor layers
• Holes are the primary charge carriers in a PNP BJT.


  True
• In which direction does current flow in an NPN BJT when a small current is applied to the base?

  Collector to Emitter
• What is the role of a small base current in an NPN BJT?

  Allows larger current
• What are the three regions of operation for BJTs?

  Cutoff, Active, Saturation
• In the active region, a BJT acts as an amplifier
• Match the BJT type with the correct description of its collector current (Ic):

  NPN BJT ↔️ Flows from Collector to Emitter

  PNP BJT ↔️ Flows from Emitter to Collector
• BJTs can be connected in three main configurations: Common Emitter, Common Collector, and Common Base
• Match the BJT configuration with its primary advantage:

  Common Collector ↔️ Impedance matching

  Common Base ↔️ High-frequency circuits
• Which BJT configuration is most suitable for voltage and current amplification in audio circuits?

  Common Emitter
• A small current is applied to the Base of an NPN BJT to control its operation.


  True
• In the cutoff region, there is negligible Collector-Emitter current because no Base current is applied.
• Order the regions of operation based on increasing base current:

  1️⃣ Cutoff

  2️⃣ Active

  3️⃣ Saturation