Condenser is a multi-purpose term that can refer to a number of instruments or parts relating to the scientific, optical, or electronics field. Generally, a condenser is something that condenses a gas into a liquid. This is a practical application to use in engines, appliances, and scientific laboratories, often for the purpose of cooling a system. By creating the transfer of a substance from gas to liquid, heat is released and removed from the system.

In refrigerators, the condenser is a set of tubes that appear to be coiled, which may be visible under the fridge, on its basckside, or sometimes is built-in to the unit and not visible at all. It functions as the refrigerant gas travels through it, causing the gas to turn to liquid, and giving off heat which is pulled away by the fins. In this sense, refrigeration is more about removing heat, rather than cooling the air, per se.http://www.repairclinic.com/Refrigerator-How-Things-Work#ACondenser

In an air conditioner, the condenser is used, just as with other applications, to turn cooling chemicals from gases into liquids, thereby removing heat and circulating it away from the unit (using the fan blades that are visible on most cooling units). The condenser is located on the outdoor portion of the air condition unit, and accepts the hot, high-pressured gas that comes from the compressor. Once the condenser does its job of turning that hot gas into cooler liquid, the liquid flows into the evaporator where the liquid is changed back into a gas (which is then used to directly cool the home or building).http://www.energyquest.ca.gov/how_it_works/air_conditioner.html

Condensers in power plants act by taking the steam that is the exhaust from the turbines and from the refrigeration units and cooling the vapors by passing them through coils.

There are also condensers used with viewing the visible spectrum, these condensers in microscopes direct the light through a projection lens. This is to focus the light onto the specimen to magnify it. When using a condenser lens it works best in magnification of 400x and above. http://www.microscope-microscope.org/basic/microscope-parts.htm>

The microphone condenser will convert sound waves into an electrical signal. It is the most common type of microphone used in studios today. Many people in the business consider them to have a greater frequency response. This is important because it reproduces the speed of the voice or instrument. They are generally only in use in the studio setting because of their sensitivity to sound interference.

Condenser Microphones are high-quality microphones that are often used in a studio setting where maximum performance is required. Condenser mics, which can also be known as "capacitors", store energy as an electrostatic field, converting acoustical energy into electrical energy. In order to function, these microphones must be powered by a battery or electrical source.http://www.mediacollege.com/audio/microphones/condenser.html

These mics are not as rugged as, say dynamic microphones, which can take a sound beating and still perform well, but Condenser Mics have a lot going for them. Their frequency response and transient response is very fast, allowing the sounds of instruments to be reproduced clearly and cleanly. They are very sensitive to loud sounds, and are therefore rarely used outside the studio, as they would likely be too sensitive for concert stages where there would be a large amount of distortion.http://homerecording.about.com/od/microphones101/a/mic_types.htm

The cost of condenser microphones is generally higher than dynamic microphones, although cheaper, low-quality models are available on the market.