Wheatstone bridge function

Fig. 21 The variation of the balancing tunneling current of the four branches four electrodes monomolecular Wheatstone bridge connected as presented in (a). In (b), the dashed line is for the current intensity 7W (in absolute value) measured by the ammeter A and deduced from the standard Kirchoff laws calculating each molecular wire tunneling junction resistance of the bridge one after the other from the EHMO-ESQC technique. In (b), Hie full line is the same tunnel current intensity but obtained with the new intramolecular circuit rules discussed in Sect. 2. (c) The resistance of the branch used to balance the bridge as a function of its rotation angle. The minimum accessible resistance by rotation is 78 MQ for the short tolane molecular wire used here...

Thus, the sensitivity of a thermistor is a quadratic function of operating temperature. The optimum sensitivity is typically 4% °C 1. Because of their nonlinear response, thermistors are sometimes linearized by placing a resistor of similar nominal value in parallel with the thermistor, with a resulting loss of sensitivity. This is not generally necessary for thermochemical sensors, particularly for the push-pull applications, because the temperature range involved is small. For direct temperature measurement, the detection limit of 10 4oC can be achieved with a conventional Wheatstone bridge. 

The thermostat is an iron box about thirty centimeters square filled with molten lead. An iron blade keeps the lead stirred and a platinum resistance thermometer functions both as a thermometer and as a thermoregulator. The Wheatstone bridge, which contains the resistance thermometer as one arm, is adjusted for a given temperature, and the beam of light from the galvanometer strikes a zero reading on the scale. At this position is introduced a photoelectric cell connected with a radio tube and amplifier, which in turn actuates an electro-magnetic relay. When the temperature reaches the predetermined value, the beam of... 

The two thermistors on which the solution droplet and the solvent droplet are placed are arranged in an Wheatstone bridge circuit in such a way that the temperature rise can be measured very accurately as a function of the bridge imbalance output voltage, AV. The operating equation is... 

Polysilicon and NiCr are currently used for high volume production of high pressure sensors. Because the origin of the change in resistance as a function of the applied strain is different for the two materials, we will analyze the physical contributions to the gauge factor and then discuss these materials in more detail. The Wheatstone bridge, which is commonly used to detect small changes in resistance, is also discussed. 

The standard method to measure impedance values as a function of the potential is the Wheatstone bridge (Figure 4.13). The electrochemical cell is placed in one branch of the bridge. In the second branch a variable resistance and a variable capacitance are placed. An alternating current is applied to a potentiostat. In the reference circuit, capacitance and resistance are varied until the bridge current, measured with an AC instrument or an oscilloscope, is zero. 

The composites are analyzed by means of complex impedance spectroscopy as the total Impedance is a function of temperature and frequency. Impedance measurements are often made with a Wheatstone bridge type of apparatus in which the resistance, R , and capacitance, C of the sample are balanced against variable resistors and capacitors. The central problem with this measurement arises over the interpretation of the data. This is because the sample and the electrode arrangement is electrically a black box whose equivalent circuit (i.e. its representation by some... 

In most cases, three-wire RTDs are used in the industry, so these will be considered here. Mainly, bridge circuits using a modified Wheatstone bridge are used. In these circuits, measured output voltage is a function of the RTD resistance. Requirements for RTDs are similar to thermocouples. Use of a double-channel AC barrier with parameters discussed later will be a cost-effective solution. 

Figure 5.13, Overall resistance of Wheatstone bridge as a function of the cross-flow resistance. (Reproduced from [172] with permission.)...

The heat losses as a function of the adiabatic deviation, Ta - 7 b. was measured (upper left in the diagram) and calibrated for each temperature. The sample temperature was determined with the platinum resistance thermometer, using a precision galvanometer and a Wheatstone bridge, indicated at the top right. The heat input into the sample, was... 

Figure 11.12 Schematic diagram of the Wheatstone bridge common-mode cancellation method. is the heater, is the variable resistor, Vq is the fnndamental signal from the function generation, and is the differential output voltage sent to the lock-in amplifier...

---