Page 305 - Concise Encyclopedia of Robotics

Solar Power
Air has a property called the dielectric constant. This is a measure of how
well the atmosphere can hold an electric charge.Air also has an ionization
potential; this is the energy required to strip electrons from the atoms.Many
things can affect these properties of air. Common factors are humidity,
pressure, smoke, and changes in the relative concentrations of gases.
A smoke detector can work by sensing a change in the dielectric
constant, and/or the ionization potential, of the air. Two electrically
charged plates are spaced a fixed distance apart (see the illustration). If
the properties of the air change, the plates gain or lose some of their
electric charge. This causes momentary currents that can actuate alarms
or robotic systems.
See also FIRE-PROTECTION ROBOT and SENTRY ROBOT.
Charged plates

Current Micro-
detector computer Robot

Alarm

Smoke detection

SOCIETY
See INSECT ROBOT.

SOLAR POWER
Electric power can be obtained directly from sunlight by means of photo-
voltaic cells. Most photovoltaic cells, also called solar cells, produce about

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