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  2. Potential gradient - Wikipedia

    en.wikipedia.org/wiki/Potential_gradient

    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).

  3. Membrane potential - Wikipedia

    en.wikipedia.org/wiki/Membrane_potential

    For such typical negative membrane potentials, positive work is required to move a positive charge from the interior to the exterior. However, thermal kinetic energy allows ions to overcome the potential difference. For a selectively permeable membrane, this permits a net flow against the gradient. This is a kind of osmosis.

  4. Electrochemical gradient - Wikipedia

    en.wikipedia.org/wiki/Electrochemical_gradient

    An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consists of two parts: The chemical gradient, or difference in solute concentration across a membrane. The electrical gradient, or difference in charge across a membrane.

  5. Chemical potential - Wikipedia

    en.wikipedia.org/wiki/Chemical_potential

    i.e., the external potential is the sum of electric potential, gravitational potential, etc. (where q and m are the charge and mass of the species, V ele and h are the electric potential [15] and height of the container, respectively, and g is the acceleration due to gravity). The internal chemical potential includes everything else besides the ...

  6. Scalar potential - Wikipedia

    en.wikipedia.org/wiki/Scalar_potential

    This means that gravitational potential energy on a contour map is proportional to altitude. On a contour map, the two-dimensional negative gradient of the altitude is a two-dimensional vector field, whose vectors are always perpendicular to the contours and also perpendicular to the direction of gravity.

  7. Electric dipole moment - Wikipedia

    en.wikipedia.org/wiki/Electric_dipole_moment

    The electric field of the dipole is the negative gradient of the potential, leading to: [7] = (^) ^. Thus, although two closely spaced opposite charges are not quite an ideal electric dipole (because their potential at short distances is not that of a dipole), at distances much larger than their separation, their dipole moment p appears ...

  8. Graded potential - Wikipedia

    en.wikipedia.org/wiki/Graded_potential

    Graded potentials that make the membrane potential more negative, and make the postsynaptic cell less likely to have an action potential, are called inhibitory post synaptic potentials (IPSPs). Hyperpolarization of membranes is caused by influx of Cl − or efflux of K +. As with EPSPs, the amplitude of the IPSP is directly proportional to the ...

  9. Diffusion current - Wikipedia

    en.wikipedia.org/wiki/Diffusion_current

    where D is the diffusion coefficient for the electron in the considered medium, n is the number of electrons per unit volume (i.e. number density), q is the magnitude of charge of an electron, μ is electron mobility in the medium, and E = −dΦ/dx (Φ potential difference) is the electric field as the potential gradient of the electric potential.