Show standard lyv type of tuned radio frequency outfit the growing tendency to use high voltages in audio frequency amplifiers often results in the application of the same voltages to the radio frequency tubes due clue to the fact that separate binding hofts for the indio frequency and audio frequency ill B positive taps are arc not provided tor for tit in many sets the accompanying illustration shows a convenient comen lent r and nd practical method of varying the voltage on the radio fre quency tubes by tile tiie use of a I 1 gh resistance the circuit shown Is not tit nc lint but Is a standard type of tuned rt re o fre quency outfit illustrated to show sho where tile the high resistance should b bo e 40 ua W a tj j V method of varying an radio frequency tubes connected in such 0 n set the same idea Is to intermediate trages of a or to other forms forma of kridlo cation where the amplification voltage Is between 90 00 and the resistance may be onus mr 01 much lower values usually will wiil give the desired results the ilic principal point to bt considered in choosing such a re ElStAD CC Is 18 its ita ability to RO 90 down to fairly low values of resl stance otance nola that tho the variable resistance resl blance to la connected in ili series with tile alio supply to the radio frequency tubs only tile DO 00 volt tap in the illustration connecting to the audio frequency tubes directly if any var variable lable resists nee of suitable value may ic be used in tills this manner to control voltage on it II F tubes the it 11 shows tile resistance si the Bradley olini and the flip CIn are others which should serve satisfactorily clevelend news |