ece323lab209

# ece323lab209 - ECE 323: Project 2, Fall 2009 Write-up Due:...

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ECE 323: Project 2, Fall 2009 Write-up Due: 10/6 1 University of Massachusetts Department of Electrical and Computer Engineering ECE 323 Electronics I Fall 2009 Project 2: Design of a Bipolar Amplifier Even before Charlie Circuitmaker finished his peak detector, he started thinking about his next project. In ECE323 he was learning about bipolar amplifiers, so he decided to build one. He proudly took his design to Dr. Designsalot who thought for a minute about how to respond. Finally Dr. Designsalot said it was a good start, but that transistor designs must account for variation between devices. Charlie then made a design that could accommodate variation in temperature and Beta. 1.0 Charlie’s First Design Figure 1: Simple Amplifier Charlie started designing his amplifier with the topology in Fig. 1, a circuit he saw in ECE323 lecture. This design gives him three values to adjust: the DC value of the input voltage (V in ), the base resistance (R B ) , and the collector resistance (R C ). Charlie decided to design for maximum voltage swing with a gain of 100 and 10k Ω collector resistor. To start with the voltage swing, he looked at how the output would reach its minimum and maximum values. When the transistor is turned off, the output voltage is equal to the supply voltage. When the transistor is in saturation, the output voltage is at its lowest at 0.2V. So, the maximum symmetric voltage swing is when the circuit is biased at (V CC -0.2V)/2. He wrote an equation in terms of V IN , R B , and R C for the output to be biased at this maximum swing voltage. Then he looked at the gain from V in to V out . His formula was in terms of Beta, R B , and R C . He was designing for a Beta of 100 and R C =10k Ω , so he solved for the value of R B . Then he used the equation he derived from his swing analysis to calculate the DC value of V IN . Draw Charlie’s circuit labeling all the component values. Show how you calculated your component values and be sure to justify any assumptions.

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ECE 323: Project 2, Fall 2009 Write-up Due: 10/6 2 2.0 Design Specifications Charlie proudly showed his design to Dr. Designsalot. The good doctor praised Charlie for coming up with a design, but expressed some concerns about how the design
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## This note was uploaded on 10/27/2011 for the course ECE 323 taught by Professor Oliai during the Fall '07 term at UMass (Amherst).

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ece323lab209 - ECE 323: Project 2, Fall 2009 Write-up Due:...

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