Hi, All of this talk has, to some extent, confused current, charge and one particular charge carrier, the electron. Any movement of charge is, by definition, an electrical current. Charge is always associated with particles of matter, never with massless particles such as photons. Charge is carried by many fundamental particles: electron, proton, positron, antiproton, as well as by unstable or inseparable particles such as quarks. The stable particles, electrons, positrons, protons and antiprotons, each carry a unit of charge. Quarks carry 1/3 or 2/3 (plus or minus) of electrical charge. Quarks do not have stable existences unless they're combined in certain groups of three, which always yield unit (+/- 1) charge quantities. In everyday electronics (*), the only charge carrier that matters is the electron, and it carries negative charge. The direction of current flow is dictated by the sign of the charge associated with the carrier and the potential (voltage) difference that drives the charge motion. This is analogous to how mass naturally moves "downhill" (from region of higher gravitational potential energy to a region of lower potential energy, though gravity is not bipolar, so there's only attraction, and it has no dual as electricity and magnetism are duals). When current it is carried by electrons, which carry negative charge, it flows from a region of more negative potential (which we conventionally symbolize with a minus sign) to a region of less negative or more positive potential (symbolized by a plus sign). In order for there to be a potential difference between two places, there must be a non-zero resistance between them (were there zere resistance, current would flow until the potential was equalized). In order for current to flow, there must be a finite resistance (and a non-zero potential difference). (*) There's something that might seem like an exception here when it comes to semiconductors. In doped semiconductor materials there can be either an excess of free or conduction-band electrons (yielding so-called N-type material) or a deficit of conduction-band electrons (yielding P-type materials) w.r.t. the pure semiconductor element. The distinction is what gives the semiconductor junction its special properties and makes possible all of what we call "solid state" electronics (a name coined to distinguish it from vacuum tube devices that preceded it and which are now used solely for very high power or high power + high frequency uses). Still, the only charge carrier that matters in known or foreseeable technology is the electron and electronic devices, whether they're semiconductor-based, vacuum tube-based or electromechanical are legitimately deemed "electronic." Sometimes I miss working with hardware. There's something nice about knowing when your design has a bug by simply seeing the smoke curling up from your prototype... And then there's tantalum electrolytic capacitors. What fun! As for the ambi-directional DC current, I suspect that's just some crank with too much time on his hands and insufficient grounding in electrostatics and electrodynamics--the math is pretty hairy, especially for AC systems with reactive components. RRS -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org