electronics An electronic device that can store electrical
charge. The charge stored Q in Coulombs is related to the
capacitance C in Farads and the voltage V across the capacitor
in Volts by Q = CV.
The basis of a
dynamic RAM cell is a capacitor. They are
also used for power-supply smoothing (or "decoupling"). This
is especially important in digital circuits where a digital
device switching between states causes a sudden demand for
current. Without sufficient local power supply decoupling,
this current "spike" cannot be supplied directly from the
power supply due to the inductance of the connectors and so
will cause a sharp drop in the power supply voltage near the
switching device. This can cause other devices to malfunction
resulting in hard to trace
glitches.
(1995-04-12)