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| university:courses:alm1k:alm-lab-11m [20 May 2015 14:26] – [Hardware Setup:] Doug Mercer | university:courses:alm1k:alm-lab-11m [07 Feb 2022 15:45] (current) – [Procedure:] Doug Mercer |
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| ======Activity 11M: The Source follower (NMOS)====== | ======Activity: The Source follower (NMOS) - ADALM1000====== |
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| =====Objective:===== | =====Objective:===== |
| {{ :university:courses:alm1k:alm_lab11m_e1.png?150 |}} | {{ :university:courses:alm1k:alm_lab11m_e1.png?150 |}} |
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| From the equation we can see that in order to obtain a gain close to one we can either increase R<sub>L</sub> or decrease r<sub>s</sub>. We also know that r<sub>s</sub> is a function of I<sub>D</sub> and that as I<sub>D</sub> increases r<sub>s</sub> decreases. Also from the circuit we can see that I<sub>D</sub> is related to R<sub>L</sub> and that as R<sub>L</sub> increases I<sub>D</sub> decreases. These two effects work counter to each other in the simple resistive loaded emitter follower. Thus to optimize the gain of the follower we need to explore ways to either decrease r<sub>s</sub> or increase R<sub>L</sub> without effecting the other. It is important to remember that in MOS transistors I<sub>D</sub> = I<sub>S</sub> ( I<sub>G</sub> = 0 ). | From the equation we can see that in order to obtain a gain close to one we can either increase R<sub>L</sub> or decrease r<sub>s</sub>. We also know that r<sub>s</sub> is a function of I<sub>D</sub> and that as I<sub>D</sub> increases r<sub>s</sub> decreases. Also from the circuit we can see that I<sub>D</sub> is related to R<sub>L</sub> and that as R<sub>L</sub> increases I<sub>D</sub> decreases. These two effects work counter to each other in the simple resistive loaded source follower. Thus to optimize the gain of the follower we need to explore ways to either decrease r<sub>s</sub> or increase R<sub>L</sub> without effecting the other. It is important to remember that in MOS transistors I<sub>D</sub> = I<sub>S</sub> ( I<sub>G</sub> = 0 ). |
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| {{ :university:courses:alm1k:alm_lab11m_e2.png?400 |}} | {{ :university:courses:alm1k:alm_lab11m_e2.png?400 |}} |
