A number of digital thermometer exist possess accuracy limitations on the transaction of in order to one hundred milli-degre c. The accuracy limitations of such digital thermometers is mainly due to quantizing error and noise of analog-to-digital convertors which follow thermistor bridges, or by inherent limitations related to other arrangements and actions.
U.S. Terry. No. 3,781,869 to Sudnick et al discloses a transducer amplifier with automatic balance for strain gages because transducers in quarter, half or full bridge configurations which gives an analog output suited for measurement, control or display purposes. The amplifier includes temperature compensation provided the silicon PN junction whose voltage-temperature characteristic is effect the offset associated with the integrated circuit amplifier stage. A signal for zero balance is made from the amplifier output which usually sampled and retained inside analog to digital converter and reconverted to analog form.
U.S. Dab. No. 4,022,063 to West et al discloses an electromechanical digital thermometer. In operation, temperature probe 10 is put into a patient's mouth inducing the thermistor therein to change resistance. Stay together unbalance in bridge 13 amplified by amplifiers 14 and 15 and thus driving motor 21. Shaft 25 then takes up a new position until resistance of potentiometer 26 fed back to the bridge balances brand new value of this thermistor reluctance. The angular associated with the shaft 25 and coding disc 22 is indicative of the temperature for this thermistor.
U.S. Sprinkle. No. 4,443,117 to Muramoto et al discloses a measuring apparatus wherein an amplifier is connected between a bridge circuit and an analog to digital converter followed with a data processor and display device.
U.S. Sprinkle. No. 4,618,848 to Parfitt discloses an analog to digital converter circuit which upon CMOS multiplexer, an analog to digital convertor and an operational amplifier buffer which is controlled by a single chip microprocessor.
U.S. Terry. No. 4,679,162 to Ferber et al discloses an assortment linear to log converter with a microcomputer manipulate. The microcomputer provides slope corrections and applies the output corrections for offsets mainly because of the circuit components and ambient temperature compensation for increased exactness.
U.S. Pat. No. 4,814,692 to Baumann discloses a circuit for measuring and digitizing the value of a weight training. The resistance being measured is both core part of an A/D converter which are operating in accord with the charge balancing network and it's also also an important part of the resistance network bridge. The circuit permits both a pure resistance measurement and attainment of a composite measured value out of a plurality of measured appreciates.
In spite of the developments and advance inside the prior art, there remains a wish of a hd digital thermometer capable of measuring temperature difference along at the order a number of micro-degrees c.
Although the present invention recently been described with reference to particular means, material and embodiments, from the foregoing description, one skilled an art can simply ascertain the essential characteristics with the present invention and various changes and modifications end up being the made in order to the various uses and scenarios without departing from the spirit and scope on the present invention as explained the claims which undertake.