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university:courses:electronics:electronics-lab-11 [22 Jan 2019 14:17]
amiclaus [Discussion:] add ltspice files
university:courses:electronics:electronics-lab-11 [12 Jul 2019 13:37]
andreeapop [Activity 11. The Emitter follower (BJT)]
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-====== Activity ​11. The Emitter follower (BJT) ======+====== ActivityThe Emitter follower (BJT) ======
  
 ===== Objective: ===== ===== Objective: =====
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 The concept in this circuit is that R<​sub>​2</​sub>​ acts as current sense resistor. When the load current times R<​sub>​2</​sub>,​ the sense voltage, reaches about 0.6 (for silicon transistors ) Q<​sub>​2</​sub>​ begins to conduct and increases current in R<​sub>​1</​sub>​ which limits ​ the base drive to Q<​sub>​1</​sub>​reducing ​ its output current. The maximum current from the circuit is reached when I<​sub>​L</​sub>​*R<​sub>​2</​sub>​ = 0.6. This circuit can be used to protect amplifiers (including push pull amplifiers.),​ power supplies and other circuits; or it can be used as a constant current circuit. This is not a precision circuit; however it is a simple and effective circuit. ​ The concept in this circuit is that R<​sub>​2</​sub>​ acts as current sense resistor. When the load current times R<​sub>​2</​sub>,​ the sense voltage, reaches about 0.6 (for silicon transistors ) Q<​sub>​2</​sub>​ begins to conduct and increases current in R<​sub>​1</​sub>​ which limits ​ the base drive to Q<​sub>​1</​sub>​reducing ​ its output current. The maximum current from the circuit is reached when I<​sub>​L</​sub>​*R<​sub>​2</​sub>​ = 0.6. This circuit can be used to protect amplifiers (including push pull amplifiers.),​ power supplies and other circuits; or it can be used as a constant current circuit. This is not a precision circuit; however it is a simple and effective circuit. ​
  
 +<WRAP round download>​
 **Resources:​** **Resources:​**
   * Fritzing files: [[ https://​minhaskamal.github.io/​DownGit/#/​home?​url=https://​github.com/​analogdevicesinc/​education_tools/​tree/​master/​m2k/​fritzing/​bjt_emitter_ff_bb | bjt_emitter_ff_bb]]   * Fritzing files: [[ https://​minhaskamal.github.io/​DownGit/#/​home?​url=https://​github.com/​analogdevicesinc/​education_tools/​tree/​master/​m2k/​fritzing/​bjt_emitter_ff_bb | bjt_emitter_ff_bb]]
   * LTspice files: [[ https://​minhaskamal.github.io/​DownGit/#/​home?​url=https://​github.com/​analogdevicesinc/​education_tools/​tree/​master/​m2k/​ltspice/​bjt_emitter_ff_ltspice | bjt_emitter_ff_ltspice]]   * LTspice files: [[ https://​minhaskamal.github.io/​DownGit/#/​home?​url=https://​github.com/​analogdevicesinc/​education_tools/​tree/​master/​m2k/​ltspice/​bjt_emitter_ff_ltspice | bjt_emitter_ff_ltspice]]
 +</​WRAP>​
  
 **Return to Lab Activity [[university:​courses:​electronics:​labs|Table of Contents]]** **Return to Lab Activity [[university:​courses:​electronics:​labs|Table of Contents]]**
  
  
university/courses/electronics/electronics-lab-11.txt · Last modified: 12 Jul 2019 13:37 by andreeapop