Page 32 - Bebop to The Boolean Boogie An Unconventional Guide to Electronics Fundamentals, Components, and Processes

Conductors and Insulators 13

entering one end of the wire and causing an equivalent electron to be ejected
from the other end is extremely fast.'
As opposed to a conductor, a substance which does not conduct electricity
easily is called an insulator. Materials such as rubber are very good insulators
because the electrons used to form bonds are tightly bound to their respective
atoms.2

Voltage, Current, and Resistance
One measure of whether a substance is a conductor or an insulator is how
much it resists the flow of electricity. Imagine a tank of water to which two
pipes are connected at different heights; the water ejected from the pipes is
caught in two buckets A and 6 (Figure 3-2).

Figure 3-2. Water tank representation of voltage,
current, and resistance

1 For a copper wire isolated in a vacuum, the speed of a signal propagating through the wire is only
fractionally less than the speed of light. However, the speed of a signal is modified by a variety of
factors, including any materials surrounding or near the conductor. Signal speeds in electronic
circuits vary, but are typically in the vicinity of half the speed of light.
2 In reality, everything conducts if presented with a sufficiently powerful electric potential. For
example, if you don a pair of rubber boots and then fly a kite in a thunderstorm, your rubber boots
won't save you when the lightning comes racing down the kite string! (Bearing in mind that
litigation is a national sport in America, do NOT try this at home unless you are a professional.)