. QST . or. Resistors are ]/2 watt, 10 per centtolerance, unless otherwise specified. Capaci-tance values below ni. are in n^i. Poten-tiometers are linear-taper 1-watt , inc. — Silver mica, 5 per cent , Ci2 — 120-Mf. 250-volt — 40-Mf. 250-volt —5 henrys, 50 ma. (Stancor C-1325).CRi — 75-ma. selenium —125 volts, 50 ma.; volts, 2 amp.(Stancor ). 34 QST for also reduces the output level to the point wherethe cathode-follower grid circuit can handle thesignal without distortion. When used for lowest disto
. QST . or. Resistors are ]/2 watt, 10 per centtolerance, unless otherwise specified. Capaci-tance values below ni. are in n^i. Poten-tiometers are linear-taper 1-watt , inc. — Silver mica, 5 per cent , Ci2 — 120-Mf. 250-volt — 40-Mf. 250-volt —5 henrys, 50 ma. (Stancor C-1325).CRi — 75-ma. selenium —125 volts, 50 ma.; volts, 2 amp.(Stancor ). 34 QST for also reduces the output level to the point wherethe cathode-follower grid circuit can handle thesignal without distortion. When used for lowest distortion, the output ofeither channel is of the order of 1 to Output levels of 8-10 volts are ol)-tainahle if a few per cent distortion is increased output capability is obtained byreadjusting the oscillator cathode resistance. The total B current drain of both oscil-lators and output stages is about 16 ma. Line-voltage variations do not greatly influence the. Fig. 3 — Improjier oper-ating conditions are shownby scope traces. A — Ex-cessive oscillator tube — Excessive oscillatortube gain, but not as muchas in A. C -— Same as Bexcept with change in scopesweep speed to facilitateestimating second-harmonicdistortion by the degree ofasymmetry (V greater than1 ). I) — Optimum sym-metry (V = 1 ), minimumeven-order harmonics, low<listrtion in output. oscillator frequency; therefore voltage stabiliza-tion is not required. Larger screen by-pass andcoupling capacitors do not add particularly to theperformance of the unit since fixed-freciuencyoperation is used. Typical voltage readings taken with a are as follows: 1) B+ at output of filter = -f 120 to -(-130volts. 2) Esg = -f30 to +40 volts. 3) Ef, = -f-55 to -1-80 volts. 4) Ek (pentode) = to volt. 5) Ek (triode) = 6 to volts. Construction The chassis layout of the phase-shift oscillatoris not critical. The entiie unit is constructed on a5 X 7 X l3
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectradio, bookyear1915
