Radio mirror (Jan-Oct 1923)

R A D T O DIGEST April 28, 1923 A. B. C. LESSONS (Continued from page 11) that no dirt or foreign matter of any kind will get into the solution. To use the hydrometer, the caps of the cells are opened and the rubber tube is inserted until the end projects below the surface of the electrolyte. The bulb is then squeezed and slowly relaxed so that some of the solution can gradually rise into the glass tube. The inner stem will then float in this extracted solution, and the point on the scale on the same level with the surface of the solution will be the specific gravity. To get most accurate readings, the hydrometer should always be held at the same level as the eye, this will avoid parallax and eliminate errors resulting from looking at the stem at an angle. When taking a hydrometer reading, care should always be exercised so as not to spill any of the solution on the tops of the jars. Also the solution should always be returned to the cell from which it was taken. After a hydrometer has been used a number of times, it is always good practice to clean it well in pure water. "When not in use, a hydrometer should always be kept in a clean place, preferably a closed box, so that no dirt will get into the battery solution. Care of Storage Batteries A storage battery should always be kept in a clean dry place and where it will not be subjected to too high or too low temperatures. The tops of the cells should be kept as free from dirt and moisture as possible. In case some acid solution is spilled on the jars, this should first be wiped off with a cloth soaked with dilute ammonia or baking soda solution, and then cleaned further with pure water. The accumulation of dirt and moisture on top of the cell jars may cause currentleakage and premature exhaustion of the battery. Another important point to observe is to see that the electrolyte within the cells is always kept at the proper level. It should never be allowed to become lower than the tops of the plates, but on the other hand should always be about % to % inch above. The amount of water in the solution will constantly become less due to evaporation and electrolysis, and it will hence be necessary from time to time to replenish this. Only pure distilled water should be added to the solution, never any acid; for it is only the water that evaporates, not the acid. However, in case some of the electrolyte has been spilled, it will be necessary to add more acid. When this is necessary, the solution added to the cells should be of the same specific gravity as that still remaining. A battery should always be kept in a well charged condition in order to secure maximum capacity and longest life from it. It should never be allowed to remain in a discharged condition for any length of time, nor should it ever be discharged beyond the point at which the specific gravity drops below 1150. Best efficiency and greatest activity will always be obtained when the plates are maintained well-charged so that a minimum amount of lead sulphate can accumulate on the surface. Charging Storage Batteries The process of charging a storage battery consists of sending an electric current from some external source through the cell in a direction opposite to that in which the battery itself causes a current to flow. During this charging the active material on the plates, as well as the electrolyte, are restored to their original condition again. For charging purposes only direct current should be used. Alternating current will not do. Where a direct current light ing circuit is available, the battery can be charged directly from this line, providing, that sufficient resistance is cut in series with the battery to cut the current down to the necessary value. Unless this is done an excessively large current will flow, with the result that either the fuses are blown or the battery ruined. For charging purposes the positive terminal of the battery must always be connected to the positive side of the charging circuit. One Way to Charge In Figure 59 is illustrated a typical circuit arrangement for charging a storage battery from a 120-volt direct current lighting circuit and using incandescent lamps as a resistance for regulating the amount of current flow. As is shown, the circuit enters at the fuse block and the double-pole switch. Connected in series with the line is an ammeter used for indicating the amount of current flowing in the circuit. The current then flows through the bank of lamps (the lamps being connected in parallel) and then enters the positive terminal of the battery. The negative terminal of the battery is then connected to the negative side of the line. The number of lamps to use depends upon their size and the amount of charging current desired. An ordinary 60-watt lamp permits about one-half ampere to flow. Hence enough lamps will have to be cut in until the current is of the right value. The normal charging current it will be remembered can always be determined by dividing the ampere-hour capacity by eight. If a charging current of 6 amperes is wanted, twelve 60-watt lamps will have to be connected in parallel, and the entire group of lamps then connected in series with the battery. The battery should be allowed to remain on charge until the specific gravity has become steady at a value of -between 1275 and 1300. Rectifiers Where only alternating current is available, some device must be used for rectifying or transforming it into direct current. There are numerous types of rectifiers on the market, some are of the bulb type and others are of the vibrating reed type. The bulb type of rectifier is generally quieter and more positive in operation and less likely to give trouble. If the above, suggestions and directions are carefully followed, little trouble will be experienced in using a storage battery, and maxim efficiency and longest life will be obtained from the apparatus. THE END AERIOLA SR. STYLE TUNER UNIT Green silk on Bakelite Tubes with diagram, $5.65. REINARTZ ULTRA CIR. SET PARTS $29.50 Ultra Reinarte Tuner Unit & Diag.. $4.95, wound to specifications March 24 Eadio Digest, Ruby MicaCopper-Bakelite mounted Condensers. N. P. binding posts, .00015, 50c: .0015, 60c; .0025, 70c. Eeinartz coil Doub. green silk-Bakelite Spider, $1.65. Beinartz plate circuit chokes (triple adjustable), $1.70. Complete set Beinartz tuner & detector parts, $10.95. Tuner, Det. & 2-Stage, SIS. 90. Two-stage outfit. $8.95. GOV'T RADIO STORAGE BATTERIES New Signal Corps Edison 3-cell type BB-4, S4.50; Single Cells for W. D.-ll tubes, $1.50; 60 A. H. for W. D.-ll tubes, $5.25; 6 Volts Edison, $7.75; Edison "B" Battery single elements. 4c ea. ; double. 10c. HI-POWER AMPLIFYING TRANSFORMERS Best! Loudest! No burn-outs. $2.65 with spec diagram. GENUINE PEANUT TUBES Wonderful Det. & Amplifier. Smallest tube made (aeroplane style), 1 V. H amp. y2" dia. x 2M." long. FLEWELLING .006 COND'RS & PARTS .006 Bakelite-Ruby -Mica-Copper Calibrated Cond., 85c. Spider coils, green silk on Bakelite, $1.75 ea. NEW SPECIALS 20 OHM RHEO. FOR 201-A OB W. D.-ll tubes, $1.00. Variable grid leaks, 1/10 to 5 Megohms. 75c. HIPOWER LOUD SPEAKER & PR. BALDWIN PHONES. $10.90. Variable grid. Cond. .00025 or .0005 max., 45c. Vernier Attachment for any Var. Condenser, 95c. Armstrong Super. New 3 tube outfit. Owner sacrificing. QUALITY RADIO SHOP, RICHMOND, IND. Largest Radio Store in America Radio BUY HERE FOR LESS Largest Radio Store in America Radio Supplies purchased here are sold under a positive guarantee of satis* faction. We carry the largest new stock of first quality merchandise. RADIO CORPORATION OF AMERICA WR-21 DETECTOR AND AMPLIFIER TUBES 4 VOLT FILAMENT, 7 AMPERE. FORMALLY EQUIPPED IN AERIOLA GRANDS. FITS WD-11 SOCKET, OR STANDARD SOCKET WITH ADAPTOR. WR-21 DETECTOR r„. $3.95 WR-21 AMPLIFIER ... 4.25 THESE TUBES WILL OPERATE ON 6 VOLT STORAGE BATTERY Complete Parts for Ultra Audion Circuit (&3?3£5t) $11.90 FREUND'S WONDER CIRCUIT $13.20 COMPLETE PARTS FOR REINARTZ SETS $11.45 COMPLETE PARTS FOR 2 STEP AMPLIFIER . . $12.45 WD-12 TUBES $6.50 The Genuine WD-11 Tube Equipped with Standard Base to Fit Standard Socket ADAPTORS FOR WD-11 AND WR-21 TUBES 50c Moulded Variometers $3.45 180° Moulded Variocouplers $3.45 Mahogany Variometers $1.95 180° Bakelite Variocouplers $1.75 Freshman Variable Grid Leak and Condenser »..75e CRL Adjustable Grid Leak and Dubilier Condenser '.. $1,35 Master Baldwin Type C Units with Cord $3.95 Master Baldwin Type C. Head Sets. . . .$6.95 Brandes Superior Headset $5.75 Antenella Aerial Plus $1-15 3 Coil Honeycomb Mounting $3.45 2 Coil Honeycomb Mounting = ....$2.60 WD-11 Bakelite Sockets 50c Barchass Coils $1.95 Firth Cord Tip Plugs 60c Thordarson Amplifying Transformers. $2.95 $6.50 Radio Corporation of America New and Improved Radiotron Tube. UV-199 DSrfi*nd TUBE Operates on 3 Volts (2 Dry Cells); Consumes M (1/16) Ampere. Same Characteristics for Sensitiveness and Loudness as UV-201. Socket for UV-199 Tube 75c Complete Parts for Knocked Down Receiving Set $17.95 COMPLETE PARTS FOR FLEWELLING CIRCUIT $12.45 VARIABLE CONDENSERS $4.30 Value, 43 PLATE, now $1.75 $3.70 Value, 23 PLATE, now ..$1.45 $3.30 Value, 1 1 PLATE, now $1.35 $3.10 Value, 5 PLATE, now $1.25 $2.70 Value, 3 PLATE, now $1.15 $7.00 Value, 43 PLATE Vernier Variable Condenser $3.95 $6.50 Value, 23 PLATE Vernier Variable Condenser $3.45 $6.00 Value, I 1 PLATE Vernier Variable Condenser $2.95 Radiotron UV-201-A Tubes, 6 Volt Filament, .25 (M) Ampere. .Cfi Cft Formerly Sold for $9.00 *p\J»*JM Operates on 6 Volt Storage Battery or 4 Dry Cells in Series U.S.A. SIGNAL CORPS (Aviation Type 194-W) WESTERN ELECTRIC PHONES, $7,95 Each Phone Cap is covered with soft rubber ear cushions, and an aviation leather helmet goes with each set! These are the only phones to pass the Government specifications for sensitiveness and loudness, the requirements called for in aircraft reception. ORIGINAL BALDWIN PHONES These are the Genuine Nathaniel Baldwin "Mica Diaphragm" Phones, complete <JQ QC with silk cord and headband. Special at «p£7.»7*J Genuine Baldwin "Mica Diaphragm" Type "C" Loud Speaking Units. &A CC i>p2C13.1 .,,,,,,,,,.,.........♦...,................«••...•■•..#••.•«•..••••■..•••••..».,#« T^ 3000 Ohm GUARANTEED HEADSETS, $8.50 Value $3.65 MAGNAV0X, LOUD SPEAKERS, Type R3 . . . $27.45 150 Turns 60 100 Turns 50 75 Turns .40 50 Turns .40 35 and 25 Turns 40 .$0.35 . .50 JACKS Pacent Single Circuit Pacent Double Circuit Federal Single Circuit Filament Control .35 Federal Double Circuit Filament Control 90 HONEYCOMB COIL 1,500 Turns ' $1.50 1,250 Turns 1.50 1,000 Turns 1-25 750 Turns 1.00 250 Turns .75 CABINETS MAHOGANY AND WALNUT 6x554" by 6" deep $1.45 6x Wi" by 6" deep 1.95 6x14" by 6" deep 2.45 6x1654" by 6" deep 2.95 6x22" by 6" deep 2.95 9x12^" by 7" deep 3.95 9x10^" by Sy2" deep 2.95 Rheostats 45c Sponge Rubber Ear Caps, Pair 50c Dials, 2, 3 and 3Yz Inch 25c Grewol Detectors $1.65 Signal Corps Super Sensitive Microphone Transmitters $2.45 Solid Copper Aerial Wire, 100 ft 35c Spaghetti Tubing, yard 10c Lightning Arresters 95c 2-Slide Tuning Coils, at $1.95 Phone Caps, for mostly all phones.... 25c Anti-Capacity Switches $1.50 Lightning Switches $2.65 Hydrometers, now at 45c Formica Panel, H" thick, black or brown, square inch . . 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