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High-precision laboratory measurements of electrical quantities are used in experiments to determine fundamental physical properties such as the charge of the electron or the speed of light, and in the definition of the units for electrical measurements, with precision in some cases on the order of a few parts per million. Less precise ...
General purpose instrument measures voltage, current and resistance (and sometimes other quantities as well) Network analyzer: Measures network parameters Ohmmeter: Measures the resistance of a component Oscilloscope: Displays waveform of a signal, allows measurement of frequency, timing, peak excursion, offset, ... Psophometer
Chronoamperometry is the technique in which the current is measured, at a fixed potential, at different times since the start of polarisation. Chronoamperometry is typically carried out in unstirred solution and at the fixed electrode, i.e., under experimental conditions avoiding convection as the mass transfer to the electrode.
The burden voltage can be significant in very low-voltage circuit areas. To check for its effect on accuracy and on external circuit operation the meter can be switched to different ranges; the current reading should be the same and circuit operation should not be affected if burden voltage is not a problem.
A different probe technique is needed for high frequency signals. A high frequency oscilloscope presents a matched load (usually 50 ohms) at its input, which minimizes reflections at the scope. Probing with a matching 50-ohm transmission line would offer high frequency performance, but it would unduly load most circuits.
Photometric quantities derive from analogous radiometric quantities by weighting the contribution of each wavelength by a luminosity function that models the eye's spectral sensitivity. For the ranges of possible values, see the orders of magnitude in: illuminance, luminance, and luminous flux. Photometers of various kinds:
These two examples show that an electrical potential and a chemical potential can both give the same result: A redistribution of the chemical species. Therefore, it makes sense to combine them into a single "potential", the electrochemical potential , which can directly give the net redistribution taking both into account.
Automated cell counters sample the blood, and quantify, classify, and describe cell populations using both electrical and optical techniques. Electrical analysis involves passing a dilute solution of the blood through an aperture across which an electrical current is flowing.