Wiki

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
university:courses:electronics:text:chapter-9 [06 Jun 2017 17:23]
_deletedUser0_ [9.4.5 Voltage Follower (common collector or drain) Lab Activities]
university:courses:electronics:text:chapter-9 [06 Jun 2017 17:26] (current)
_deletedUser0_ [9.3.4 Output impedance, current follower or common base/gate amplifier]
Line 171: Line 171:
 Again looking at the small signal models in figure 9.3.1 we see that for both the BJT case and the MOS case the output impedance is the parallel combination of R<​sub>​L</​sub>​ and r<​sub>​o</​sub>​. We can generally assume this is true if we consider that V<​sub>​in</​sub>​ is driven from a low impedance (nearly ideal) voltage source. If this is not the case then the finite output impedance must be added in series with r<​sub>​o</​sub>​. If the input of the current follower is driven by the relatively high output impedance of a transconductance amplifier such as the common emitter or source amplifier from earlier then the output impedance for the combined amplifier can be very high. For most practical applications we can ignore r<​sub>​o</​sub>​ because it is very often much larger than R<​sub>​L</​sub>​. ​ Again looking at the small signal models in figure 9.3.1 we see that for both the BJT case and the MOS case the output impedance is the parallel combination of R<​sub>​L</​sub>​ and r<​sub>​o</​sub>​. We can generally assume this is true if we consider that V<​sub>​in</​sub>​ is driven from a low impedance (nearly ideal) voltage source. If this is not the case then the finite output impedance must be added in series with r<​sub>​o</​sub>​. If the input of the current follower is driven by the relatively high output impedance of a transconductance amplifier such as the common emitter or source amplifier from earlier then the output impedance for the combined amplifier can be very high. For most practical applications we can ignore r<​sub>​o</​sub>​ because it is very often much larger than R<​sub>​L</​sub>​. ​
  
 +**ADALM1000 Lab Activity, [[university:​courses:​alm1k:​alm-lab-cb|BJT Common Base Amplifier]]**\\
 +**ADALM1000 Lab Activity, [[university:​courses:​alm1k:​alm-lab-cg|BJT Common Gate Amplifier]]**\\
 +**ADALM1000 Lab Activity, [[university:​courses:​alm1k:​alm-lab-fca|Folded Cascode Amplifier]]**
 ==== 9.4 Voltage followers (also called Emitter or Source follower or Common collector or drain amplifiers) ==== ==== 9.4 Voltage followers (also called Emitter or Source follower or Common collector or drain amplifiers) ====
  
university/courses/electronics/text/chapter-9.txt · Last modified: 06 Jun 2017 17:26 by _deletedUser0_