Miscellaneous active electrical nonlinear devices – circuits – and – Signal converting – shaping – or generating – Having specific delay in producing output waveform
Patent
1995-05-03
1996-12-10
Sikes, William L.
Miscellaneous active electrical nonlinear devices, circuits, and
Signal converting, shaping, or generating
Having specific delay in producing output waveform
327 91, 204408, 204416, H03H 1126, G11C 2702, G01N 2726
Patent
active
055834620
ABSTRACT:
A method and apparatus for rapidly measuring chemical properties of a solution using a plurality of devices having relatively long thermal time constants selectively coupled to a control means. Current I.sub.d flows through only one device at a time. A timing logic control circuit controls the timing of the drain switch and, if present, the reference switch. The output of the multiplexing circuit is sampled a precise amount of time after each device begins conducting current. The temperature at the sample time is a constant. The characteristics of the solution in which the device is immersed is the only variable in the operation of the device (i.e., I.sub.d, and V.sub.ds are held constant). By sampling the output a predetermined amount of time after the device has been turned on, the temperature rise is controlled. In this way, the effects of temperature rise due to conduction on the device are constant at each sample time and can be neglected, and the characteristics of the solution can be precisely determined without waiting for the temperature to stabilize.
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Nguyen Tiep H.
Sikes William L.
Unifet Incorporated
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