IKh r mnnfrlmnt iL
1500-3000 Li O.I5h T IOil of amp .tuBe Fig. 15-89. Amplifier-coupling filter for tuned-filter harmonic analyzer. components, which is usually true. It helps to make possible the measurement of a small second harmonic in the presence of a large fundamental. A singly tuned filter does not tune sharply enough to make possible measurement of the amplitude of a small-amplitude component whose frequency does not differ greatly from that of a large-amplitude component. To overcome this difficulty...
Type Phototube 1
0 10 20 30 40 50 60 70 80 90 e Anode Voltage Fig. 13-22. Anode diagram for the type 918 gas phototube. 0 10 20 30 40 50 60 70 80 90 e Anode Voltage Fig. 13-22. Anode diagram for the type 918 gas phototube. current may be expanded in an infinite series similar to the plate-current series for an amplifier tube. It is difficult, however, to evaluate the coefficients of such an expansion in the solution of problems. It is more practical to determine the output voltage and harmonic content by means...
U
Fig. 12-2. Tubes for the production of modulated light. If the electrode spacing and gas pressure are correct, the outer surface of the cathode is uniformly covered with glow. Another type of tube is the crater lamp illustrated in Fig. 12-2b. The cathode consists of a solid cylinder which fits within a thin cylindrical anode and is separated from the anode by mica, and in the outer end of which is a cone-shaped depression. The design is such that, the discharge takes place between the 1 See,...
Ce rWC ln
At a given value of C, Ce has its maximum value when r is zero. The effective resistance shunting Ce is then infinite and the effective capacitance is It is evident that very large values of effective capacitance can be obtained with this circuit if A is large. Since A may be varied by means of the bias of one or more grids of a stage to which inverse feedback is not applied, the value of the effective capacitance may be readily varied. The input voltage E must, of course, be maintained low...
Info Svy
Fig. 9-37. a Essential steps in communication by means of a-m waves. b Block diagram of the superheterodyne receiver. Fig. 9-37. a Essential steps in communication by means of a-m waves. b Block diagram of the superheterodyne receiver. from the rectification or transrectification characteristics at the operating point, in exactly the same way that the plate resistance, transconductance, and amplification factor are found from the static plate characteristics. A bridge for the dynamic...
Vck Application
Values change with ratio of load resistance to series inductance. voltage but requires four filament transformers. In the double three-phase rectifier with balance coil, induced voltages in the balance coil cause equal currents to flow simultaneously in two phases, one in each wye. This results in low average and peak tube currents, but the peak inverse tube voltage is comparatively high. Many other connections are possible, some of which give increased efficiency or improved voltage...
Oq H O
Table 14-1. Characteristics of Rectifier Circuits Used with Inductance Load See first paragraph of Sec. 14-4 for explanation of items listed. Two-phase full-wave four-phase star Three-phase double star six-phase star full-wave Double three phase with balance coil
Phototube Operated Relay
ZQO v.r-m-s-i a-IIO i .- gt Fig. 13-36. Circuit diagram for Prob. 13-1. 13-2. The following data apply to a photoelectrically controlled relay a. Draw the diagram of a circuit in which increase of illumination will cause the relay to be opened. All phototube and amplifier voltages are to be derived from a single 220-volt d-c supply. b. Specify values of resistance that will provide the correct filament current and suitable values of plate voltage and adjustable biasing voltage. c. Specify the...
Phototube Operated Relay
Frequency,--Dynamic response curve for type 868 gas phototube. Fig. 13-9. Lag in response of a gas phototube. Frequency,--Dynamic response curve for type 868 gas phototube. The third disadvantage resulting from the use of gas in phototubes is caused by the relatively large mass of the positive ions. Because the time taken for a positive ion to pass from the vicinity of the anode to the cathode is appreciable, there is a perceptible time lag in the response to a change in flux. The manner in...
Exhaust Tube
THE TUBE IS EVACUATED THRU THE ORIFICE OR SMALL HOLE IN THE TOP OF THIS GLASS EXHAUST TUBE THE EXHAUST TUBE IS THEN SgALEP OFF AT THE BOTTOM ENO OR TIP BY FUSING THE END OF THE GLASS.__ THE AIR AND OTMEf GASES ARE PUMPED FROKf THE ENTIRE SPACE UNTIL PRACTICALLY A PERFECT VACUUM IS OBTAINED._ TOP CAE SOLDER THE GR10 LEAD IS SOLDERED TO THE TOP CAP. THIS GIVES A SMOOTH FINISH AND PERFECT ELECTRICAL CONTACT_
LmJL
Fig. 9-14. Graphical explanation of linear plate modulation. excitation to the plate. Complete rectification takes place because of plate-current cutoff. This type of modulation is called linear plate modulation plate-voltage modulation . The circuit of the linear plate modulator is similar to that of Fig. 9-2, but the modulation input transformer is in the plate circuit, instead of in the grid circuit. A graphical explanation of the operation of the circuit may be given with the aid of Fig....
lrLC where C CiCCi C the resultant capacitance of Ci and Ci in series The
and Ci, and the inductances of the chokes are made large enough so q4 that they do not appreciably affect the oscillation frequency. As a variable-frequency oscillator the Colpitts oscillator is less convenient to use than the tuned-plate, tuned-grid, or Hartley oscillators, owing to the necessity of varying both Ci and C2 in order to maintain oscillation. It has been found suitable for use in marine work, because the condensers may be sealed against moisture and the circuit tuned by means of a...
Info Nzx
-Composite plate characteristics for the type 47 power pentode at two values of grid bias. voltage of 180 volts, and -50- and 40-volt grid bias. The composite characteristics of pentodes do not approximate straight lines, as may be seen from the suppressor- and beam-pentode characteristics of Figs. 7-17 and 7-18. It is evident from the method of deriving the composite characteristics and from Fig. 7-16, that, when the two tubes are alike and the circuit is symmetrical, the composite plate...
C
Fig. 4-11. Circuit in which the a-c re- Fig. 4-12. Circuit in which the a-c resistance between the terminals exceeds the sistance between the terminals is less than d-c resistance. the d-c resistance. Since the slope of the a-c load line is equal to l rb, the coordinates of any two points on this line must differ by amounts Aei, and Aib such that Ae amp A rb. If the dynamic operating point is known, the line may be constructed by drawing it through the operating point and any other point whose...
Info Xtu
Koehler, G. Electronics, February, 1936, p. 14. Everitt, W. L. Proe. I.R.E., 24, 305 1936 . Fay, C. E. Proc. I.R.E., 20, 548 1932 . Osbokn, P. H. Proc. I.R.E., 20, 813 1932 . Everitt, W. L. Proc. I.R.E., 22, 152 1934 . Terman, F. E., and Ferns, J. H. Proc. I.R.E., 22, 359 1934 . Miller, B. F. Proc. I.R.E. 23, 496 1935 . Mouromtseff, I. E., and Kozanowski, H. N. Proc. I.R.E., 23, 752 1935 . Terman, F. E., and Koake, W. C. Proc. I.R.E., 24, 620 1936 . Reed, M. Wireless Eng., 12, 296 1935 . Scott,...
AVERAGE PLATE CHARACTERISTICS Rkp
Fie. A-11.- Average plate characteristics for the types 76 and 56 triodes. T i r TYPE 6 SO 7 Screen volts 100 Suppressor volts 0 T i r TYPE 6 SO 7 Screen volts 100 Suppressor volts 0
Theory of Grid Action in Triodes Equations for Plate and Grid
a- High neg. grid voltage b- Medium neg. grid voltage a- High neg. grid voltage b- Medium neg. grid voltage c- Zero grid voltage d-Small positive grid voltage Fig. 3-3. Approximate field distribution resulting from applied voltages in a triode with plane parallel electrodej for fixed positive plate voltage and four values of grid voltage. Arrows indicate the direction of the force on an electron. c- Zero grid voltage d-Small positive grid voltage Fig. 3-3. Approximate field distribution...
grid After extinction these electrons are trapped on the grid and the
condensers C and C'3, making the grid voltage highly negative. A positive pulse of voltage applied to the input reduces the negative grid voltage for an instant and allows the tube to fire. If desired, the condenser C may be omitted and the tube fired by discharging C2 in any manner or by applying an impulse to the grid through a transformer in series with C2. This circuit is useful in the production of voltage and current surges of various shapes.1 The wave form is dependent upon the portion...
Western Electric Tube D96475
Fig. 15-23. Inverted vacuum-tube voltmeter. 15-10. Inverted Voltmeter. A very useful meter for the measurement of high voltages has been described by Terman.1 This meter is called the inverted voltmeter because the usual functions of the grid and the plate are interchanged. Its action depends upon the fact that the grid current which flows when a positive voltage is applied to the grid of a triode may be controlled by negative plate voltage. Figure 15-23 shows the method of measuring high...
V Kdd
target that fluoresces, of varying angular width, meter where rough measurements suffice, is used as a tuning indicator, the a-v-c biasing voltage, which increases with amplifier output, is used as the control voltage. 1 Waller, L. C., and Richards, P. A., Radio Retailing, December, 1935, p. 47 Thompson, H. C., Proc. I.R.E., 24, 1276 1936 Waller, L. C., QST, October, 1936, p. 35, November, 1936, p. 23 Waller, L. C., RCA Rev., 1, 111 1937 . 15-27. Determination of Static Tube Characteristics. It...
The tungsten sensitivity of a phototube is the ratio of the anode current at a
lumens entering the tube from a tungsten-filament lamp operated at a color temperature of 2870 K. Variational sensitivity of a phototube is the ratio of the change in anode current at a specified steady anode voltage to the change in the total luminous flux entering the tube. As most precisely used, the term refers to infinitesimal changes, as indicated by the defining equation It is evident that the variational sensitivity is the slope of the curve of current vs. flux at given values of anode...
Info Ixg
Fig. 12-87. Circuits for producing voltage pulses for thyratron control. conduct.1 If T2 were omitted, the voltage induced in coil C would tend to maintain current flow in Ti during the whole cycle and thus prevent the variation of saturating current by phase control of Ti. 12-46. Voltage Impulses for Grid Control. When it is very important that the thyratron fire at exactly the same point in the cycle in succeeding cycles, it is sometimes desirable to use a fixed negative grid bias and to fire...
Magnetostriction Oscillator
Fig. 10-74. Impedance-stabilized oscillator of generalized form. greater frequency stability was found experimentally for a tightly coupled oscillator than for a loosely coupled one. The form of the equations for stabilizing capacitance shows that for most types of oscillators it is necessary to vary the stabilizing capacitance with the tuning capacitance when adjustable frequency is required. When grid or plate stabilization alone is used, the required stabilizing capacitance is proportional...
moving object will appear to be stationary when examined by the light
The requirements of such a light source are 1 easily controlled frequency of illumination, to allow synchronization of light and motion over a large frequency range, 2 extremely short duration of light flash, so that the moving part under observation will not appear to move while it is illuminated, and 3 light of great brightness, so that the moving part will be clearly seen despite the short time of illumination. By acting as a shutter of extremely high speed, the stroboscopic light source...
Glowtube Protective DevicesAnother interesting application of the glow tube is
surge voltages.1 Connected across the apparatus, the glow tube serves as a by-pass for surge voltages above the ignition potential of the tube. It is evident that the extinction potential should be higher than the normal voltage of the apparatus which it protects, in order that the tube may extinguish when the surge is over. Heating of the electrodes may cause the glow to change into an arc. For this reason a current-limiting resistance must be provided if the circuit is capable of supplying...
Puckle Electron Tube Sawtooth Generator
Fig. 10-43. Static family of screen characteristics for a type 57 tube. The dotted lines show dynamic screen characteristics for the circuit of Fig. 10-41, derived under the assumption that changes of screen and suppressor voltage are equal. Dynamic curves of ic2 vs. ec2 for the circuit of Fig. 10-41 may be readily derived from the static family of ic2- 2 characteristics.1 Thus, in Fig. 10-43, the dotted dynamic ic2-ec2 curves are obtained by connecting points for which ec2 and ecz are changed...
Ijzz
Equation 6-8 may be readily transformed into the equivalent equation Equations 6-8 and 6-9 and their rationalized equivalents are too complicated to show clearly the influence of the various circuit constants upon the voltage amplification. The formulas for special forms of the impedance-capacitance-coupled amplifier are considerably simpler. Fig. 6-9. Two-stage resistance-capacitance-coupled amplifier. Fig. 6-9. Two-stage resistance-capacitance-coupled amplifier. 6-5....
Puckle Sawtooth Triode
Fig. 10-23. Typical wave forms of plate-to-plate voltage in a symmetrical multivibrator. Fig. 10-23. Typical wave forms of plate-to-plate voltage in a symmetrical multivibrator. Fig. 10-24. Typical wave forms of a grid-to-grid voltage and b plate-to-plate voltage in an asymmetrical multivibrator. when the plate resistors are large and the grid resistors small it is of the form of Fig. 10-236 when the plate resistors are small and the grid resistors large. Typical curves of grid-to-grid and...