Radio Broadcast - 1924, January - 84 Pages, 8.2 ... - VacuumTubeEra

A Two-Stage Amplifier for Your Receiver 253amplifier end. The trouble was in the jacks.the drill holes with the aid of a3.06and marking.The jacksprings were not of spring stock and failed to return toposition. The result was a failure to make contact,thus leaving the circuit for the amplifier open. Thejack was removed and the springs bent to make propercontact, but this measure could only be temporary.There is no more troublesome part to replace in a radioset than a jack, or a piece more vital in its proper functioning.HOW TO CHOOSE THE PROPER RHEOSTATHE lawTconnecting volts, amperes, and ohms(known as Ohm's law) is expressed as follows:ohms =voltsamperesThis law applies to the whole circuit or to any partof it.The table below shows that a \JV-igg tube requires3.0 volts 0.06 ampere. We can compute its resistanceby Ohm's law. It isvolts= ohms or3-Qamperes.06= 50 ohmsIf this tube is to be operated from a 4-5-volt battery(three dry cells in series) the extra 1.5 volts (4.5 3.0)must be taken by the rheostat. Since the tube and therheostat are in series, the current in the rheostatshould also be 0.06 amperes when the correct voltageis obtained. We can then compute the resistance requiredin the rheostat by Ohm's law. It isvolts= ohms or1.5amperes .06= 25 ohmsThe rule for determining the resistance required in arheostat is therefore as follows:Subtract the volts required by the tube from the volts atthe battery.what greater than that computed and adjustit down tothe required value.Approximate D. C. characteristics of popular tubes:EIRTYPE(VOLTS) (AMP) (OHMS)2006i6MAIN PANEL20166ithem together. If this "pattern, or20 1 -A6.2524Divide the remainder by the tube amperes.It is best to select a rheostat with a resistance some-'992I5-AWD-iiWD-I2i-51-51-5.25.25.2550666