Resistivity is a constant for a material as opposed to resistance which is dependent on size considerations. This is analogous to specific heat capacity and heat capacity. It can be said that resistivity is more useful for comparison because other factors (size) have been accounted for.
In the case of using the four-probe method to measure the thickness of a thin film:
ρ = (V/I) x (thickness of film) x (correction factor)
We measure the current and voltage using the four-probe method, from which we can get the resistance between the probes. Knowing the resistivity, which is constant for the material and can be obtained from sources such as books, will enable us to relate the resistance to the dimensions of the film.
use a reference digital thermometer with a probe that can measure 1800C. actually use 5 probes to measure the different areas inside the chamber...measure then compute for the uncertainties....
get into tight places,measure high-magnitude currents,monitor currents at a remote location,open a circuit
The same as the function of analog multimeter, but with greater precision and accuracy.measure voltage (both DC and AC)measure current (both DC and AC)measure resistanceSome digital multimeters can also do other things:measure capacitancemeasure inductancemeasure frequencymeasure temperature remotely (usually using a thermocouple probe)measure current without breaking the circuit (using a clip on magnetic probe)test semiconductor devices (diodes, junction transistors, field effect transistors, etc.)AF and/or RF signal generatoretc.
Thermometer for temperature; or temperature probe; measuring cylinder, burette, pipette for volume; electronic balance for mass; pH probe for acidity; spectrophotometer for colour wavelength; mass spectrometer for relative mass The list is endless.
Thats the linear range of the probe
One disadvantage of the two-probe method to measure resistivity is that it can introduce errors due to contact resistance at the probe-sample interface. Additionally, the measurement may not accurately capture the true resistivity of the sample if the probe spacing is large compared to the sample size. Finally, the two-probe method is not suitable for measuring resistivity in materials with high contact resistance or non-uniform resistivity distributions.
The four probe method involves using four separate electrical contacts to measure the resistivity of a sample, allowing for more accurate measurements by reducing contact resistance effects. The method is called "four probe" because there are four contacts used to measure the sample's resistance, providing a more precise way to determine the energy band gap of a material like germanium crystal.
The four probe method involves using four electrical contacts to measure the resistivity and conductivity of a semiconductor sample. By applying a known current and measuring the voltage drop across the sample, the band gap can be indirectly determined by analyzing the temperature-dependent resistivity data. The band gap of the semiconductor can be inferred by observing a change in resistivity at a certain temperature range, corresponding to the activation energy required for electrons to jump from the valence band to the conduction band.
I assume you are referring to methods of measuring small value resistances, as in locating short circuits on a PC card. Two probe is the method used by standard ohm meters. This works OK for most resistance values, as the resistance of the leads & probes is much lower than the resistance being measured. But when the resistance being measured gets very tiny (e.g. a few milliohms) it fails as the resistance of the leads & probe are of the same order of magnitude and are in series with it. Four probe solves this problem by using two probes connected to a current source to drive the resistance and a separate two probes connected to a precision voltmeter calibrated in milliohms. The voltage drop in the leads due to the test current does not get measured by the calibrated voltmeter, as it does in two probe method. There is no voltage drop in the measurement leads as the voltmeter is high impedance.
the question is wrongfour prob is better than two prob method as it eliminates the effect of wire imbedance as well as contact resistance
The resistance of an ideal oscilloscope probe is infinity.
Never probe airbag wiring with a power probe or multi-meter unless you have isolated the circuit by disconnecting both the airbag module and airbag component. As long as you have disconnected these you will be fine.
In general, line resistance = resistivity * line length / (line cross-sectional area). Check the unit consistency: for the right-hand side, [ohm-m] * [m] / [m^2] = [ohm]. The resistivity of the material should be given. You can measure it with a large chunk of the material using a four-point probe, simplistically speaking. You can also look up the value online.
To read a soil compaction test probe, insert the probe into the soil to the desired depth, then compare the resistance encountered while inserting and removing the probe. High resistance indicates compacted soil, while low resistance suggests loose soil. Record the depth at which resistance changes occur to assess soil compaction levels.
A pH probe is a device used to measure the acidity of a solution.
Psychotherapy.
Air Probe.