Wiki

Differences

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

Link to this comparison view

Both sides previous revision Previous revision
Next revision Both sides next revision
university:courses:alm1k:alm-lab-13a [27 Jan 2021 22:35]
Robin Getz use wp> interwiki links
university:courses:alm1k:alm-lab-13a [06 Sep 2021 16:20]
Doug Mercer [Another Configuration:]
Line 91: Line 91:
 =====Another Configuration:​===== =====Another Configuration:​=====
  
-Remembering the loop formed by the base emitter voltages of Q<​sub>​1</​sub>,​ Q<​sub>​2</​sub>,​ Q<​sub>​3</​sub>​ and Q<​sub>​4</​sub>​ we also know that the order of the voltage drops around the loop can be interchanged. So if we interchange the V<​sub>​BE</​sub>'​s of NPN Q<​sub>​1</​sub>​ and PNP Q<​sub>​3</​sub>​ we get the configuration shown in figure 3. Some of you may recognize the combination of Q<​sub>​3</​sub>​ and Q<​sub>​2</​sub>​ as the low offset follower we discussed earlier in the lab section on emitter followers. The circuit uses the V<​sub>​BE</​sub>​ shift up of a PNP emitter follower to partially cancel the V<​sub>​BE</​sub>​ shift down of an NPN emitter follower. Transistors Q<​sub>​1</​sub>​ and Q<​sub>​4</​sub>​are simply the complement of Q<​sub>​3</​sub>​ and Q<​sub>​2</​sub>​.+Remembering the loop formed by the base emitter voltages of Q<​sub>​1</​sub>,​ Q<​sub>​2</​sub>,​ Q<​sub>​3</​sub>​ and Q<​sub>​4</​sub>​ we also know that the order of the voltage drops around the loop can be interchanged. So if we interchange the V<​sub>​BE</​sub>'​s of NPN Q<​sub>​1</​sub>​ and PNP Q<​sub>​3</​sub>​ we get the configuration shown in figure 3. This arrangement is sometime referred to as a "​diamond buffer"​ because of the shape formed by the four emitter / base connections. Some of you may recognize the combination of Q<​sub>​3</​sub>​ and Q<​sub>​2</​sub>​ as the low offset follower we discussed earlier in the lab section on emitter followers. The circuit uses the V<​sub>​BE</​sub>​ shift up of a PNP emitter follower to partially cancel the V<​sub>​BE</​sub>​ shift down of an NPN emitter follower. Transistors Q<​sub>​1</​sub>​ and Q<​sub>​4</​sub>​ are simply the complement of Q<​sub>​3</​sub>​ and Q<​sub>​2</​sub>​.
  
 {{ :​university:​courses:​alm1k:​alm-lab-13a_f3.png?​500 |}} {{ :​university:​courses:​alm1k:​alm-lab-13a_f3.png?​500 |}}
university/courses/alm1k/alm-lab-13a.txt · Last modified: 24 Jan 2023 20:02 by Doug Mercer