1. A device that converts a gas to a liquid to obtain either the substance or the released heat.
2. A lens or mirror used to concentrate light; such as, onto a transparency or specimen.
3. A chamber enclosing an array of tubes into which the exhaust steam from a steam engine is distributed and condensed by the circulation of cooling water through the tubes.
4. In refrigeration, a heat exchange coil within a mechanical refrigeration system used to reject heat from the system; this is the coil where condensation takes place.

1. Capacitors that consist of tiny storage batteries which charge and discharge rapidly.

Made of two plates separated by a thin insulator or sometimes air, when one plate is charged negative and the other positive, a charge builds up and remains after the current is removed.

When electric power is required, the circuit is switched to conduct current between the plates, and the electrical charge is released.

2. An electronic component that stores an electric charge and releases it when required.

It comes in a huge variety of sizes and types for use in regulating power as well as for conditioning, smoothing, and isolating signals.

Capacitors are made from many different materials, and just about every electrical and electronic system uses them.

1. A capacitor in which an electrolyte serves as a plate; the other plate is wound aluminum foil.

A thin layer of oxidation on the foil is the dielectric.

2. A capacitor having an electrolyte between two plates.

A thin layer of oxide is deposited on only the positive plate. The oxide acts as the dielectric for the capacitor.

Electrolytic capacitors are polarized and so they must be connected in correct polarity to prevent a breakdown; so, although electrolytic capacitors have comparatively high values of capacitance for their sizes, they also have a high leakage of current and therefore must often have their polarities checked.

An electromechanical device formerly used for compacting direct-filling gold; such as, gold foil restorations in prepared tooth cavities.

1. A microphone consisting essentially of a flexible metal diaphragm and a rigid metal plate that together form a two-plate air capacitor.

Sound waves set the diaphragm in vibration, producing capacitance variations that are converted into audio-frequency signals by a suitable amplifier circuit.

2. A microphone design where a condenser (the original name for a capacitor) is created by stretching a thin diaphragm in front of a metal disc (the back plate).

By positioning the two surfaces very close together an electrical capacitor is created so the capacitance varies as a function of sound pressure.

Any change in sound pressure causes the diaphragm to move, which changes the distance between the two surfaces.

Electrostatic microphones, unlike other types, require a battery or other voltage source.

A speaker in which mechanical forces are produced by the action of electrostatic fields.

1. A transducer consisting of a set electrode and a movable electrode, charged electrostatically in opposite polarity.

The motion of the movable electrode changes the capacitance between the electrodes and so makes the applied voltage change in proportion to the amplitude of the electrode's motion.

2. A transducer which consists of a capacitor, at least one plate of which can be set into vibration.

Its operation depends on the interaction between its electric field and a change in its electrostatic capacity.

A condenser for a steam engine, in which the vacuum is maintained by the downward flow of water through a vertical pipe of great height.