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university:courses:electronics:electronics-lab-8a [23 Aug 2019 12:54] Antoniu Miclaus |
university:courses:electronics:electronics-lab-8a [20 Jul 2022 20:35] Doug Mercer [Objective:] |
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| ====== Activity: A Floating (two terminal) Current Source / Sink ====== | ====== Activity: A Floating (two terminal) Current Source / Sink ====== | ||
| - | ===== Objective: ===== | + | =====Objective:===== |
| The objective of this activity is to investigate the ΔV<sub>BE</sub> concept to produce an output current which is stabilized (less sensitive) to variations of the input voltage level. Feedback is used to build a circuit which produces a constant or regulated output current over a range of supply voltages | The objective of this activity is to investigate the ΔV<sub>BE</sub> concept to produce an output current which is stabilized (less sensitive) to variations of the input voltage level. Feedback is used to build a circuit which produces a constant or regulated output current over a range of supply voltages | ||
| + | =====Background:===== | ||
| + | |||
| + | The [[adi>media/en/technical-documentation/data-sheets/AD590.pdf|AD590]] is a 2-terminal integrated circuit temperature transducer that produces an output current proportional to absolute temperature. The schematic diagram of this floating current source is shown in figure 7 of the AD590 datasheet. The a simplified and less accurate version of this concept is used as the experimental circuit in this activity. | ||
| + | |||
| + | The AD590 uses a fundamental property of silicon BJT transistors to realize its temperature proportional characteristic. If two identical transistors are operated at a constant ratio of collector current densities, r, then the difference in their base-emitter voltage is (kT/q)(In r). Because both k (Boltzman’s constant) and q (the charge of an electron) are constant, the resulting voltage is directly proportional to absolute temperature (PTAT). For more details please refer to the datasheet. | ||
| ===== Materials: ===== | ===== Materials: ===== | ||
| ADALM2000 Active Learning Module\\ | ADALM2000 Active Learning Module\\ | ||
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| <WRAP round download> | <WRAP round download> | ||
| **Resources:** | **Resources:** | ||
| - | * Fritzing files: [[ https://minhaskamal.github.io/DownGit/#/home?url=https://github.com/analogdevicesinc/education_tools/tree/master/m2k/fritzing/float_current_source_bb | float_current_source_bb]] | + | * Fritzing files: [[downgit>education_tools/tree/master/m2k/fritzing/float_current_source_bb | float_current_source_bb]] |
| - | * LTspice files: [[ https://minhaskamal.github.io/DownGit/#/home?url=https://github.com/analogdevicesinc/education_tools/tree/master/m2k/ltspice/float_current_source_ltspice | float_current_source_ltspice]] | + | * LTspice files: [[downgit>education_tools/tree/master/m2k/ltspice/float_current_source_ltspice | float_current_source_ltspice]] |
| </WRAP> | </WRAP> | ||
university/courses/electronics/electronics-lab-8a.txt · Last modified: 20 Jul 2022 20:35 by Doug Mercer