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The simplest definition for a potential gradient F in one dimension is the following: [1] = = where ϕ(x) is some type of scalar potential and x is displacement (not distance) in the x direction, the subscripts label two different positions x 1, x 2, and potentials at those points, ϕ 1 = ϕ(x 1), ϕ 2 = ϕ(x 2).
A potentiometer with a resistive load, showing equivalent fixed resistors for clarity. The potentiometer can be used as a voltage divider to obtain a manually adjustable output voltage at the slider (wiper) from a fixed input voltage applied across the two ends of the potentiometer. This is their most common use.
A potentiometer being calibrated and then measuring an unknown voltage. R 1 is the resistance of the entire resistance wire. The arrow head represents the moving wiper.. In this circuit, the ends of a uniform resistance wire R 1 are connected to a regulated DC supply V S for use as a voltage divider.
The string potentiometer may be connected as a three-wire tapped resistor (voltage divider), in a control circuit, or may be packaged with electronics to produce a measurement signal in a useful form, such as a variable voltage 0-10 VDC, variable current 4-20mA, pulse encoder, Bus (DeviceNet and Canbus) and RS-232 communications.
Position vectors r and r′ used in the calculation. The starting point is Maxwell's equations in the potential formulation using the Lorenz gauge: =, = where φ(r, t) is the electric potential and A(r, t) is the magnetic vector potential, for an arbitrary source of charge density ρ(r, t) and current density J(r, t), and is the D'Alembert operator. [2]
The electric potential and the magnetic vector potential together form a four-vector, so that the two kinds of potential are mixed under Lorentz transformations. Practically, the electric potential is a continuous function in all space, because a spatial derivative of a discontinuous electric potential yields an electric field of impossibly ...
While quite similar to normal potentiometers, digital potentiometers are constrained by current limit in the range of tens of milliamperes. Also, most digital potentiometers limit the voltage range on the two input terminals (of the resistor) to the digital supply range (e.g. 0–5 VDC), so additional circuitry may be required to replace a conventional potentiometer, (although digital ...
Telecommunication standards define a "zone of influence" around a substation, inside of which, equipment and circuits must be protected from the effect of ground potential rise. In North American practice, the zone of influence is considered to be bounded by the "300 volt point", which is the point along a telecommunications circuit at which ...