conduction
voltage is a disturbance... energy that needs to be released
resistance is how well it allows that energy to go
-how well can you utilize that voltage?
quickly or slowly? with resistance, takes a tax on it
speed and spacing of electrons: net flux the same
positive end: electrons moving fast (low electron density)
negative end: electrons moving slower (higher electron density)
not a great difference in speed, but it is there.
lower density of electrons: lower potential
voltage difference:
excess electron density at one terminal
inversely proportional to spacing (larger or smaller of that of atoms)
same voltage difference may not require same density difference (capacitance). geometry effects it.
REFLECTIONS are bad... characteristic impedance prevents them. stereos.
CURRENT can determine VOLTAGE in a current source.
-applied current can force a VOLTAGE. enforced by wire geometry.
note voltage drop along line (voltage decreases linearly).
standing waves...forward and backward waves... one from load to source. superposition.
GEOMETRY OF WIRE.
MAIN PRINCIPLES:
1) inertia/momentum
2) coulomb force
3) relativistic delay in signal propagation
the force field must be streaming continuously out of the electron
Anticipitory behaviour of electrons... weird. can't stand scrutiny. therefore, electrons carry info about themselves. series of readjustments.
acceleration disturbance -- other electrons get the original's acceleration, therefore original's velocity.
field pushed/pulled -- a gap or "doubling up" can occur.
propagation of gap... gap pulls A, gap continues.
FORCE: that initial hit that provides an acceleration :). only being accelerated while being touched. As soon as contact over, constant velocity.
aaah.... parallel "brigades" of electrons. as electrons move forward, high electron density. each brigade senses the density of its neighbors... wants to move outwards, to surface of wire.
i see... moving electrons are actually rarefied/compressed near locus of disturbance.
VOLTAGE source: maintains a spacing difference between terminals. net charge density to create potential difference.
-regardless of velocities
-however, must balance flow. otherwise flux different, which will eventually restore balance as charge builds up.
-voltage source launching electrons (providing them with initial acceleration). note that electrons pull each other along.
CURRENT source: maintains ratio of velocity to spacing. (same flux)
electron acceleration essentially instantaneous. much smaller than propagation time between electrons (.23 nm between atoms)
wire can become negative or positive.
barrier -- like electron at end of wire (no place to go).
electron "bounces" off the end of the barrier.
send negative signal in both directions, even though electrons always going to right. close and "more close".
get DOUBLE the initial voltage in an open-ended wire. Electrons bunch up on each other more than they were initially given.
YES, wires must get negative... they are at the same potential as the battery
because electrostatic force so strong, even a TINY change in spacing (due to relativistic effects -- the delay in signal propagation) has a LARGE effect on voltage. wow.
RAREFICATION approaches resistor at same speed as COMPRESSION. comes from both sides.
must have faster electrons in RAREFIED part (to keep the flux the same).
potential gradient exists along resistor. electrons ACCUMULATE at one end, rare at the other. potential GRADIENT. special circumstances inside resistor.
only ONE value of resistor can perform balancing act.
CAPACITOR: voltage source doesn't know that it can't conduct yet :). same as open line.
