Making the most of your receiver Eddystone Stratton VK7AG 0010
Recognised text
Text below was produced by optical character recognition and may contain errors. Check it against the original.
ISCHARGES. ienced with light- static electricity, ts are likely when receivers. With r), a condenser is n highly insulated ie. a greater liability tricity. protection against consists of carbon j in a sealed glass the Ediswan Gas irges of more than = rect one electrode andbook or folder that proper time ains in order that >» panel is correctly s in any way con- ains between 100 of a value below ; are between 200 whichever socket is very important, supply, to ensure D.C. no dial light as plug is inserted. ort of hum occurs se the mains plug 9roduction will be et to D.C. mains, , again, the mains the receiver. nance of a battery the batteries used sr attention, both the best possible orms. When the [an see.at a glance ged, the positive light grey colour. becomes a lighter iarge the cell. =n not so easy to It meter is always on of the state of Its on load should hould be charged. >r is to use what this instrument a ding a reading of “as standard in Eddystone receivers 1.15 is obtained, or greater, everything is in order, but should the value be below this, then charging is necessary. A fully charged cell will normally show a specific gravity of approximately 1.25. There are two important points to watch to ensure maximum life from the battery. One is that the level of the acid is maintained to the maker’s mark, where visible, but in any case, always above the top edge of the interior plates. The second point is not to allow the accumulator to become discharged to any great degree or to leave it in a discharged condition for any length of time. As soon as you become aware that charging is necessary, steps should be taken to put the battery on charge as quickly as possible. Eddystone battery receivers are provided with a length of cable adequate for all normal requirements. Should, however, in exceptional cases, an additional length of cable be found necessary, this cable should be of heavy gauge wire to minimise voltage drop. The top of the accumulator should be kept clean, the terminals well greased with ordinary vaseline, and the filter-vent kept screwed down tight except when the accumulator is being charged. It is important to loosen these vents whilst the cell is being charged to allow the escape of gas formed during the charging process. ; Normally, when the level of acid drops, it will only be necessary to add distilled water. Care is required during this operation to prevent the spillage of any acid, as it will have a deleterious effect on any material with which it comes into contact. From time to time, it is advisable to wash out the cells of the accumulator in order to remove the deposit at the bottom. This, if allowed to increase, might result in a partial short circuit of the cell. A sign of this is that the accumu- lator will not hold its charge properly, or that one cell always shows a much lower voltage than the others. This washing out process is best entrusted to someone used to the job, such as a garage or wireless service station. Before emptying the cells they should be in a fully charged condition, and when filling with new acid, the specific gravity of the latter should be approximately 1.25. An accumulator should always be kept in as cool a place as possible, and not exposed to direct sunlight, which is likely to have a bad effect on the chemicals inside the cells. LOUDSPEAKERS AND TELEPHONES. Because compactness is desirable, a loudspeaker is fitted internally in some Eddystone receivers, but in others, the individual is free to choose a speaker to suit’ personal requirements. An output transformer is fitted of all types—communications and broadcast. The secondary winding is brought. out to terminals or sockets, and a loud-speaker, connect- ed to the latter, should have an’ impedance of between 2 and.3 ohms. No matching transformer is required with an external loudspeaker. The Eddystone speaker illus- trated here is Zins. overall diameter and takes the form of a diecast aluminium housing, fitted with a Sins. speaker unit and also a special acoustic baffle. Three colours are available—black (Cat. No. 688), brown (Cat. No. 697) and grey (Cat. No. 698), with highly polished Fig. 12. The Eddystone Cat. No. 688 Speaker. chromium plated feet. The housing is a diecasting and the speaker This speaker is recommended matches Eddystone receivers physically and for use with an Eddystone receiver electrically. Also, of course, it can be used (communications or broadcast) with other receivers. Page Nine