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| university:courses:electronics:text:chapter-4 [06 Apr 2022 14:39] – [4.1 Precision Voltage to Current Converter] Doug Mercer | university:courses:electronics:text:chapter-4 [06 Apr 2022 14:49] (current) – [4.1.1 The Active Voltage to Current Converter] Doug Mercer |
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| Looking at equation 2, the output impedance, Z<sub>OUT</sub> will be infinity if R<sub>1</sub>=R<sub>3</sub>, R<sub>2</sub>=R<sub>4</sub> and R<sub>S</sub>=R<sub>S'</sub> because the bottom term in the ratio will be exactly zero. To the extent that the resistors do not match the output impedance could be either positive of negative. For example if R<sub>3</sub> were slightly larger than R<sub>1</sub> the bottom term would be negative. | Looking at equation 2, the output impedance, Z<sub>OUT</sub> will be infinity if R<sub>1</sub>=R<sub>3</sub>, R<sub>2</sub>=R<sub>4</sub> and R<sub>S</sub>=R<sub>S'</sub> because the bottom term in the ratio will be exactly zero. To the extent that the resistors do not match the output impedance could be either positive of negative. For example if R<sub>3</sub> were slightly larger than R<sub>1</sub> the bottom term would be negative. |
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| | More details on the Howland current source can be found in [[adi>media/en/analog-dialogue/volume-52/number-4/a-large-current-source-with-high-accuracy-and-fast-settling.pdf|A large current source with high |
| | accuracy and fast settling]] and [[adi>media/en/analog-dialogue/volume-47/number-2/articles/choose-resistors-to-minimize-errors.pdf|Choose resistors to minimize errors in grounded-load current source]]. |
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| =====4.2 Precision Current to Voltage Converter===== | =====4.2 Precision Current to Voltage Converter===== |
