Mainly About Construction

Radio Record, Volume II, Issue 24, 28 December 1928, Page 26

Mainly About Construction

Battery Connections

A Few Useful Suggestions

ALTHOUGH . and B battery eliminators ate becoming increasingly popular among radio owners, a large number are still using batteries as a soure: of filament and B-supply and will continue to do so, especially where suitable power lines are not avilable. Every set owner using batteries should know not. only how to take care of and keep them in good operatins condition, but also the proper methods of connecting them to the set to optain the best results, Battery Containers. (SORRODED terminals, acid eaten wire and wrong connections are a common source of trouble that may easily be avoided. Batteries untidily placed on thé floor, connected by long straggling wires to the set, are not only disagreeable to the eye, but also a certain source of trouble. Such an installation may be satisfactory for temporary use when testing, but should néver be permanent. Instead ef separate leads, the use of multi-wire cables, is advised and the batteries ant charger should be kept out of the way, and out of light where possible. If a radio console or tuable with battery compartment is not available, a neat closed box of suitable size, in which air holes are drilled, may be used. NH radio owner, known to the _ writer, has utilised a wash-stand with a lower compar’nent provided with folding doors. These pieces of furniture are rapidly’ being discarded and one should be procurable at an auction sale for quite a small sum. If stained to match the cabinet a very fine piece of furniture can be made. Another adaptation is the familiar kerosene box, unfortunately going out of fashion. With a few of these, a very

neat battery box can be constructed. When small sets are made a cabinet can be constructed to include batteries. Binding Posts. A TIENTION should be given to binding posts. Loose posts and poor terminal connections cause crackling noises, and high resistance contacts,

with which no radio receiver can possibly give good results. The posts may have loosened by vibration or may not have been turned down tightly when the receiver was fitst installed. All wire attached to binding posts should be perfectly clean. If rubber covered wire is to be used, clear away the insulation by slicing with a sharp knife, away from the body. and slantwise down the wire toward the end.

Other methods will lead to a wire being severed, or injured and the knife seriously bluntened. Having removed the rubber, scrape the wire, or individual wires if stranded, clear of any trace of insulation. . If the wire is tinned it is inadvisable to scrape off the tin as it saves the wire from corrosion. Stranded wire

should be twisted so that there are no stray wires. If this is now coated with solder a perfect terminal can be assured, Silk or cotton covered wire should be tied so as to prevent fraying. The wire should be bent round the post in the same direction that the head turns, that is clockwise. -This tends to keep the-wire securely under the head. .Some binding posts have a

hole drilled in the shank, through which the wire is inserted, whereupon the lead is screwed down tightly. In those cases where no hole is drilled the enterprising amateur ecah with the aid of.a 5-64in, or 8-32in. twist drill attain his ends, The wire on the innermost end of the terminal should be attached by means of a lug soldered to the wire and: attached to the terminal by means of:a small nut.. Two would be better. A good terminal is provided with a slot on this end, so that a good connection can be made. A Battery Plug. . GOOD product is to be seen on the market for a battery connéction. It consists of a socket and plug. The plug has several prongs which. fit into the socket so as to form a firm connection, this allows of all batteries being instantly disconnected. There is no fear of shorting by making a wrong connection in connecting them up again. There are other means of achieving this end. One or two valve bases and valye sockets may be pressed. into service. Take a broken or burnt out valve, ‘which unhappily, every set owner must possess, clear away the glass and sweat out the four wires from the prong. Taking four insulated strands of the cable, clear away just ‘enough insulation to allow the end to be pushed wéhy down the prong. If the cavity is not wide enough to take the wire it may be easily drilled out. If earefully. made a good battery connection "can be constructed for a very few shillings. There is another very efficient method. Take a narrow strip of bakelite or ebonite and drill to take sufficient plugs, to take leads from ‘all the batteries. Drill another piece of bakelite to take the sockets. If these are

somewhat irregularly spaced the plugs will fit one way only and there. can be no danger of a short circuit. The photograph accompanying the article illustrates the idea. The strip holding the leads and plugs can be withdrawn boldly from: the sockets when the set is finished with, and the set completely isolated, and by using good quality ebonite for the strip, there is no likelihood of any leakage taking place between the respective plugs. The idea: works admirably in practice.