- المجال: Aviation
- Number of terms: 16387
- Number of blossaries: 0
- Company Profile:
Aviation Supplies & Academics, Inc. (ASA) develops and markets aviation supplies, software, and books for pilots, flight instructors, flight engineers, airline professionals, air traffic controllers, flight attendants, aviation technicians and enthusiasts. Established in 1947, ASA also provides ...
A cap for a tire, strut, or accumulator air valve that, when screwed onto the valve, depresses the valve stem and allows the air to safely escape through a hole in the side of the cap.
Industry:Aviation
A capacitor having a high impedance to DC and low-frequency AC, but a low impedance, or a small opposition, to the AC signal being passed through the circuit.
Industry:Aviation
A capacitor that can be used only in a DC circuit. When using a polarized capacitor, attention must be paid to the polarity of the voltage to which it is connected.
Most electrolytic capacitors are polarized and are marked so they can be correctly installed in a circuit. If a polarized capacitor is incorrectly installed, enough current can flow through it to destroy it.
Industry:Aviation
A capacitor that provides a low-impedance path for alternating current to flow around, or bypass, a circuit component which is being used to produce a DC voltage drop.
Industry:Aviation
A capacitor that uses a semiconductor material as one plate, a thin film of silicon oxide as the dielectric, and a tiny spot of metal plated on the oxide as the other plate. MOS capacitors used as temporary storage devices in a digital computer are called dynamic RAMs (random access memories).
Industry:Aviation
A capacitor that uses air as the dielectric. A variable tuning capacitor in a radio is an example of an air capacitor.
Industry:Aviation
A capacitor that uses metal foil for the electrodes and an extremely thin film of metallic oxide, a nonconductor, as the dielectric. Two sheets of metal foil separated by a piece of porous paper impregnated with an electrolyte are the plates. The dielectric is an oxide film formed on the surface of one of the plates.
The capacity of a capacitor is inversely proportional to the thickness of the dielectric — the thinner the dielectric, the greater the capacity. And, since the oxide film is extremely thin, an electrolytic capacitor has a large capacity for its physical size.
One major disadvantage of an electrolytic capacitor is its low DC working voltage compared with that of other types of capacitors. The thin oxide film can be easily punctured by a high voltage. An oxide film on a piece of metal acts as a rectifier. Electrons can pass from the metal through the film into the electrolyte. But they cannot pass from the electrolyte through the film to the metal.
Because of this rectifying action, electrolytic capacitors must never be used in AC circuits, and they must be installed in a DC circuit with their anode, the terminal marked with a plus sign, connected to the positive voltage.
Industry:Aviation
A capacitor that uses two concentric tubes as the plates, or conductors, and a vacuum between the tubes as the dielectric. A vacuum capacitor has a higher breakdown voltage than a similar capacitor that uses air as its dielectric.
Industry:Aviation
A capacitor used to carry a conductor through a panel or bulkhead. The outer conductor of the capacitor is connected to the case, and the inner conductor is connected to terminals that extend from both ends of the capacitor.
Feedthrough capacitors used in some aircraft magnetos minimize breaker point arcing and also decrease the radio interference caused by electrical energy radiated from the ignition switch lead.
Industry:Aviation
A capacitor whose capacity can be changed. The capacity of a variable capacitor can be changed by varying the area of the plates, the distance between the plates, or the dielectric between the plates.
Industry:Aviation
