Glossary of Wireless Terms

Radio Record, Volume I, Issue 49, 29 June 1928, Page 13

Glossary of Wireless Terms

UNDER this heading we will give regularly sections of the glossary , of wireless terms which is a prominent feature of the N.Z. Radio Listeners’ Guide. In that book, although set in the smallest type, it oceupies some 13 pages, and is definitely in our opinion the most comprehensve and complete glossary on modern lines which has been made available in the Dominion. For the benefit of our readers the glossary will be reprinted in our columns.

BRUSH DISCHARGE.-A discharge of high-tension electricity, which takes the form of a luminous glow, | accompanied by a crackling sound. A brush discharge occurs when the voltage is almost high enongh to produce a spark or are, . . BULB RECTIFIER.-In _ battery charging appliances, a bulb_ rectifier consisting of a filament and a plate in a glass bulb having a low vacuum or specitl gas is used for the urpose of converting alternating current into impulsive direct current by cutting off the flow of those impulses or currents wvhich flow in the wrong direction. BUSBAR.-Copper wire, often tinned, used in wiring the circuits of wireless sets. It is manufactured round (diagonally) and square.. The object of its use is to enable insulation to be dispensed with ag the wires stay where put and will not fall together like flexible leads. The wiring of a radio set must be spaced correctly to achieve the best results, and stiff wire facilitates this. Often insulation Cena as spaghetti) is used on the wires as well. , : BUZZER.-An instrument consisting of a eoil of wire round a soft-iron core, near which is placed a steel reed or ar- mature. Currents flowing in the coil from a small battery magnetise the core and attract the armature, which automatically breaks the circuit, allowing the armature to return to its normal position. This.action again closes the circuit, and onee more the armature is attracted, and the vibratory action continues as long as the battery is connected in the circuit. The yibration of the armature sets up sound waves, which are heard as a musjeal note. In wireless‘it is used for testing erystal detectors, the buzzer being allowed to function while the erystal is being adjusted. When the buzzer sounds at its loudest in the phones the crystal is ready for reception. "CO BATTERY.-See "Bias."

CAPACITY.-Is the property of a de- | vice, or‘body, to store energy in electrostatic f6rm. "It is the property which a eondenser has of receiving and storing a charge of electricity. It depends upon the size of plates, the distance between them, and the nature of the substance filling the spaces. Generally referred to in terms of microfarads. Capacity is measured by the quantity of electricity that can be forced into a device, or body, by a pressure of one volt. The unit of capacity is termed a "farad." CARBORUNDUM.-aA , carborundum erystal detector has the advantage of ereat stability, but it is generally recommended that to obtain the best results a small 44 volt battery and potentiometer should be used with it. CARRIER WAVE.-Sce "Continuous W .ves" and "Modulation." CATHODE.-Sometimes spelt "Kathode." The filament or source of the electron supply in a valve. (The negative electrode.) See ‘Anode." CATWHISKER.-Is a fine piece of wixe, which may be of various kinds of metal, usually in the form of a spiral coil, used in conjunction with a detector crystal, upon which it rests when in operation. CELL.-One of the units of a battery of either wet or dry variety. CHARGE,.-Applied to the recharging of an accumulator, and also to the charging up of the plates of a condenser; in the latter application the plates charge and discharge in sympathy with the frequency of the oscillators when inserted in a high-frequency circuit. CHARGER BATTERY.-See "Rectier." CHEMICAL RECTIFIER.-Another name for an electrolytic rectifier.