Show marked progress in in vacuum tu tuber 0 G broadcasting brought rapid changes in Detec detecting tingo amplifying Dc devices vices properly dermod tile heart beart of tile the set vacuum tubes have kept pace with will the speedy progress made by the radio receiver ns as a whole models or of detecting nil and simplify ing devices that appeared shortly before the lays days of broadcasting today would hardly be recognized as radio tubes while mille the early instruments were cumbersome their delicacy required that they bo be carefully hanOi handled cd sometimes they performed but more often their life was short sonic some of ahr contained a double filament one to lip be used lit in case thu the other burned out lit in addition some did not bave a base merely having protruding wires to be soldered to tile of tile receiver which really save gave the Ini impetus petus to radio to curry carry it to its present status quickly brought rapid changes chances in the tubes the current consumption of fit the earlier types was heavy brins being one ampere per tube A tl lr tube tilbe set ct then would draw its as heavily froni from the storage sto rafie battery as do does tin the modern 12 tube tuba outfit filament changed one of the first lortt areal clin changes was tile design of it a filament that would not require so iauch current tills till model cut the consumption to one quarter ampere and lias has become tile modern standard with the c 11 a 11 uee n tile the besign of tile the filament other improvements were incorporated such a as the replacement of the lie old type metal baso with one ninde made froin frocil bakelite also tile the contact prongs at t tile the bottom of the tube were vure lengthened a to provide a better socket can connection tion further efforts saw the lie production or of special amplifiers and detectors included were the so called power tubes which with higher plate voltage gave cave greater volume tile power tube Is intended for use us as an amplifier in addison ad dilon there have appeared p irvi improved det detector octor tules tubes whose purpose Is greater ity an increase in volume costumes Con Coris less power while all of vie tile larrer larger types re cufre live volts unit tire intended for operation oper atlon from a storage battery or its equivalent similar progress tins has been b ean le it in the development of art an instrument intended use with dry coils cells two types lipes have been provided one drawing a volt ngi of 11 II 11 tile the ether bumm but W P on oil three volts power wiles olios of tills this tm also have lieen been produced attempts fieve been blinde nt at leml 1 I nation of the hie filament nt but tery providing direct current ly by hiie designs or of it tube operating from nl al current through Kli a voltage step down transformer there tins hns all kenred tin nn improved A C tube operating nt at eight volts announced is n 11 big step over tin nn earlier cm her model required four use of current u r ns as the lie heating element it 11 considerable change in tile jube bubo design tube construction lins has been exl ox tended so ns as to include ports parts of other units used in set construction |