@Hal Pollner "Electric current always flows from Negative to Positive!" When I enrolled at DeVry Technical Institute right out of high school, I already knew that. But, early on, instructors pointed out that all the symbols used in electronics had their arrows indicating current direction facing the wrong way! The dilemma was that originally, Ben Franklin made the assumption that current flows from positive to negative. We had to resolve that dilemma by referring to his thoughts as "Franklin current", and ours as "electron current". Then we had to study "holes". No, not people holes, but rather vacancies which had housed an electron, one to a hole. Thus, now, holes flowed in the opposite direction to electrons, hence holes obeyed Franklin current! Holes concepts were used early on in the semiconductor, or transistor theory. Then, there was "bubble memory"! Today we get stuff from some mysterious "cloud". Mystifying. Frank
@Frank, I've heard that DeVry is a great Technical School for both Associate and Bachelor degrees in Engineering. When we studied semiconductor theory at CSULB, we were told to visualize "holes" as the "absence of electrons", thus flowing so as to oppose actual electron flow, as you stated. "Hole Flow" was just a hypothetical concept of "anti-current". You can't measure "hole flow" with a miliammeter! Hal
@Hal Pollner DeVry was yet in infancy when I attended there. Privately-owned, semi-credited (learned later, UNLV would not accept transfer credit, I had to petition for that), one day as we sat in Lab, a school official entered accompanied by a bear of a man, older, but burly and obviously outspoken. "Shake hands with Jack Dempsey, boys!", he bellowed. I thought to myself, WTH is this? Later, I learned it really WAS the ex-prizefighter, who had bought a controlling interest in DeVry Tech! Frank