Old computers are getting to be a lost art. Here at Uncreative Labs, we
still enjoy using the old computers. Sometimes we want to see how far a
particular system can go, other times we use a stock system to remind
ourselves of what we once had.
To email me directly, send a message to puckdropper (at) fastmail.fm
A Schottky diode is sort of a half junction, It is made by coating N
type semiconductor with a metal. Schottky diodes have about half the
forward drop of a full PN junction, but also has very low reverse
voltage capability, compared to PN junction diodes.
In a normal PN junction diode, the p side injects holes into the N
side and the N side injects electrons into the P side, where these
minority carriers find their opposites and disappear. But when a
reverse bias is suddenly applied, the minority carriers turn around
and head back across the junction and must all be swept out before the
diode achieves reverse bias shut off.
Since there is no source of holes in a Schottky half junction pass to
the N type material during forward bias (metals conduct entirely with
electrons, so they simple absorb the electrons passes from the N side)
there is no reverse bias delay when the diode is reverse biased, just
a variable capacitance as the electrons are pulled back from the metal
when the N side switches to positive bias.