QT114-D QUANTUM [Quantum Research Group], QT114-D Datasheet
QT114-D
Related parts for QT114-D
QT114-D Summary of contents
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... Medical fluid sensing ! Soil moisture sensing ! AVAILABLE OPTIONS SOIC C QT114 QT114-IS QProx™ QT114 ™ RANSFER EVEL Vcc 1 8 Out1 2 7 Out2 3 6 Filt 4 5 8-PIN DIP QT114-D - Copyright © 1999 Quantum Research Group Ltd IC ENSOR Gnd Sns2 Sns1 Pol R1.03 ...
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... The QT switches and charge measurement hardware functions are all internal to the QT114 (Figure 1-2). A 14-bit single-slope switched capacitor ADC includes both the required QT charge and transfer switches in a configuration that provides direct ADC conversion. The burst length is inversely proportional to the rate of charge buildup on Cs, which in turn depends on the values of Cs, Cx, and Vcc ...
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over the operating temperature range. Figure 2-2 shows the response from a horizontal strip of the same surface area; the signal exhibits a very rapid rise in signal between points l1 ...
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... Bare probes can also be used with aqueous fluids, but in these cases a 1,000pF (1nF) ceramic NPO capacitor should be inserted between the probe and the QT114 to block DC current flows. A bare internal probe used with conductive fluids and an in-line blocking capacitor will generate a huge, robust capacitive response that will not readily permit the use of a 2-level probe due to signal saturation ...
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Figure 2-8 Single Internal Horizontal Probe Figure 2-10 Coaxial Probe For Non-Aqueous Fluids 2.2 CALE UILDUP Scale buildup on internal probes, bare or insulated, is not generally a problem since the sensor is still measuring capacitance, not conductance, ...
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... Cs. Selecting an appropriate value of Cs for a given electrode geometry is essential for solid detection stability. The QT114 employs dual threshold points set at 250 and 150 counts of acquisition signal. The signal travels in a reverse direction: increasing Cx reduces the signal counts; ...
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... If the sensor is wired to a microprocessor as shown in Figure 3-3, the microprocessor can reconfigure the load resistor to either ground or Vcc depending on the output state of the QT114, so that the pulses are evident in either state with either POL setting. S ELECTION ...
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... The currents should not be allowed to traverse the area directly under the QT114. If the QT114 is connected to an external circuit via a long 2 7 cable possible for ground-bounce to cause damage to OUT1 SNS2 the OUT pins ...
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... DMM. Repeat the test without a load to measure the capacitor's internal leakage, and subtract the internal leakage result from the voltage droop measured during the QT114 load test. Be sure the DMM is connected only at the end of each test, to prevent the DMM's own impedance from contributing to the capacitor's discharge. ...
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ABSOLUTE MAXIMUM SPECIFICATIONS Operating temp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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... Refer to QT110 datasheet for complete dimensional information 4.7 CUSTOMIZATION QT114 technology can be customized to suit specific requirement, often with little NRE charge or change in part cost. Consult your rep or the factory for further information, or email to: = recommended range, unless otherwise noted ...
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Quantum Research Group Ltd QProx, QTouch, QLevel, and HeartBeat are trademarks of QRG Ltd. Enterprise House, Southampton, Hants SO14 3XB Tel: +44 (0)23 8045 3934 Fax: +44 (0)23 8045 3939 Notice: This device expressly not for use in any medical ...