Key component in Operational Amplifiers

Transcription

1 Key component n Operatonal Amplfers

2 Objectve of Lecture Descrbe how dependent voltage and current sources functon. Chapter.6 Electrcal Engneerng: Prncples and Applcatons Chapter.6 Fundamentals of Electrc Crcuts Explan how they are treated when analyzng a crcut and provde examples.

3 Dependent Sources The output voltage or current of a dependent source s determned by one of the parameters assocated wth another component n the crcut. n ths course, the parameter s the voltage across or current flowng through of the other component. Other parameters may be the component s resstance, amount of lght shnng on the component, the ambent temperature, and mechancal stress appled to the component ncludng changes n atmospherc pressure.

4 Practcal Dependent Sources Operatonal amplfers Transstors Bpolar Juncton Transstors (BJTs) Metal-Oxde-Semconductor Feld Effect Transstors (MOSFETs) oltage and current regulators Other devces nclude: Photodetectors, LEDs, and lasers Pezoelectrc devces Thermocouples, thermovoltac sources

5 Dependent Power Sources oltage controlled voltage source (CS) Current controlled voltage source (CCS) oltage controlled current source (CCS) Current controlled current source (CCCS)

6 Power Generators Dependent voltage and current sources generate power and supply t to a crcut only when there are other voltage or current sources n the crcut. These other sources produce a current to flow through or a voltage across the component that controls the magntude of the voltage or current output from the dependent source.

7 Crcut Analyss Treat smlar to the ndependent voltage and current sources when performng nodel and mesh analyss. Do not treat lke an ndependent source when usng superposton. ndependent voltage and current sources are turned on and off as we apply superposton. Dependent sources reman on.

8 Example #: Nodal Analyss oltage controlled current source The value of the current s -x0 - tmes the voltage across.

9 Example # (con t) Note that there are no unts on the coeffcent for the dependent source. t s assumed that you know that the unts should be A/ for a CCS.

10 Example # (con t) Node A : Node B: Node C : Node D : ma x0 ma 0

11 Example # (con t) ( ) ( ) ( ) B A D A C B B B A A

12 Example # (con t) ( ) ( ) ( ) ( ) ( ) ( ) ma x ma B C B C B B B D B Node D : 0 0 Node C : Node B: Node A :

13 Example # (con t) Nodes oltages () Currents(mA) A - ma B 6 -ma C ma D -ma ma

14 Example #: Superposton s a current controlled voltage source (CCS). The value of the voltage of the CCS s 000 tmes the current, whch s the current flowng out of.

15 Example # (con t) The two crcuts that wll be analyzed are. When s on and s turned off.. When s on and s turned off. n both crcuts, s left on.

16 Example # (con t) When s turned off, one termnal of s not connected to the rest of the crcut an t can be elmnated.

17 Example # (con t) You can select any analyss to solve for.

18 Example # (con t) ( )

19 Example # (con t) ( ) ( )( ) ( )( ) ( ) Ω Ω Ω Ω k k k k

20 Example # (con t) Currents Dependent Source.mA.60-0.mA

21 Example # (con t) Agan, you can select whch ever analyss technque that you would lke n order to solve for.

22 Example # (con t) ( ) ( ) ma

23 Example # (con t) ( )( ) ( )( ) ( )( ) ( ) ( )( ) Ω Ω Ω Ω Ω k ma k k k k ma

24 Example # (con t) Currents Dependent Source 0.mA µA

25 Example # (con t) Currents Dependent Source (.0.)mA.5mA (.60.9).5

26 Summary Dependent sources are voltage or current sources whose output s a functon of another parameter n the crcut. oltage controlled voltage source (CS) Current controlled current source (CCCS) oltage controlled current source (CCS) Current controlled voltage source (CCS) Dependent sources only produce a voltage or current when an ndependent voltage or current source s n the crcut. Dependent sources are treated lke ndependent sources when usng nodal or mesh analyss, but not wth superposton.