RCA

RCA'804 is a pentode transmitting tube of the thoriated'tungsten filament type for use as an r-f amplifier, frequency multiplier, oscillator, and suppressor-, grid-, or plate-modulated amplifier. The plate connection is brought out through a separate seal at the top of the bulb to insure excellent insulation and low grid-plate capacitance. In adequately shielded circuits, neutralization to prevent feedback is generally unnecessary. The suppressor is connected to its individual base pin. RCA-804...

Diodes

The simplest form of radio vacuum tube is the two-electrode type consisting of a cathode and an anode, or plate. This type, called a diode, is used in transmitting service mainly as a rectifier to convert low-frequency a-c voltages from the power line to d-c voltages for plate, screen, and grid-bias supplies. Simple diodes, such as the 866, are called half-wave rectifiers because they rectify but one-half of each alternating voltage cycle. When two diodes are enclosed in a single envelope, the...

Tuning A Class C Rf Amplifier

Push Pull Amplifier

In general, the same adjustments are made in tuning different class C r-f amplifiers, irrespective of the type of tube or circuit used. Although the tuning of a triode r-f amplifier is described in the following paragraphs, the procedure applies almost equally well to tetrode and pentode amplifiers. In the following explanation, it is assumed that the triode has been correctly neutralized. The filament of the amplifier tube is lighted, the positive plate-supply lead disconnected , and r-f...

RF Power Amplifier Oscillator

RCA-833 is a three-electrode, high-mu transmitting tube of the thoriated-tungsten filament type for use as a radio-frequency amplifier, oscillator, and class B modulator. Because of its high perveance, the 833 can be operated at high plate efficiency with low driving power. Designed in a new way with post terminals which provide a rugged structure and make bases unnecessary, RCA-833 has a minimum amount of insulation within the tube. The plate is supported directly from its post terminal at the...

Beam Power Rf Amplifier Or Frequency Doubler

AMPLIFIER POWER OUTPUT 37 WATTS APPROX. Cl 50 MMf, WDGET C2,C3,C4,C6 0.005 if, MICA C5 2 JJjJf METER, 1200 VOLTS R 10000 OHK IS, I WATT R2 250 OHMS, 5 WATTS R3 35000 OHMS, 10 WATTS R4 20000 OHMS, 10 WATTS Li R-F CHOKE F l A. HIGH-VOLTAGE FUSE NOTE FOR FREQUENCY DOUBLING, TUNC Cj L2 TO FREQUENCY2f A 4DOOO-OHM, 10-WATT SERIES SCREEN RESISTOR CAN BE USED IN PLACE OF R3 AND R4. PUSH-PULL CLASS C R-F AMPLIFIER FOR C-W TELEGRAPHY POWER OUTPUT SO WATTS APPROX. Cl s 1.2 Mif METER SECT ION C2 0.005Mf,...

Installation And Application

The base pins of the RCA-808 fit the standard 4-contact socket, such as the RCA type UR-542A. The socket should be installed so that the tube will operate in a vertical position with the base down. The plate of the 808 shows an orange-red color at the maximum plate- dissipation rating for each class of service. The grid-leak form of bias is particularly useful in class C Telegraph Service when the 808 is operated at a plate voltage of 1000 volts or less. If the grid excitation is accidentally...

Interstage Coupling

In transmitter design, the coupling of the r-f amplifier grid circuit to the plate circuit of the driver stage is of considerable importance. In most cases, the amplifier grid is driven so that grid rectification occurs and, as a result, a direct current flows in the amplifier grid circuit. The amount of d-c grid current and driving power required depend principally on the tube type used in the amplifier, the class of service, the operating frequency, and on the plate load impedance of the...

Inp

Plate Family Curves

And is never driven negative so far that plate current is cut off. The average d-c plate current is substantially constant between the conditions of no signal and full signal. The plate efficiency, or ratio of a-c power output to average d-c power input, is relatively low for triodes about 20 to 50 per cent at full output, depending on the design of the tube and on the operating conditions. Fig. 1 illustrates class A amplifier operation. Specially designed tubes of the triode type are...

Info

As R-F Power Amplifier and Oscillator Class C Telegraphy Key-down conditions per tube without modulationtt D-C Plate Voltage 1000 max. Volts D-C Plate 150 max. Milliamperes D-C Grid Current 30 max. Milliamperes Plate Dissipation 60 max. Watts D-C Plate Voltage 600 800 1000 Volts D-C Grid VoltageS -95 -105 -110 Volts Peak R-F Grid Voltage 235 245 250 Volts D-C Plate Current 140 140 140 Milliamperes D-C Grid Current Approx. 30 30 30 Milliamperes Grid Resistor 3160 3500 3670 Ohms Driving Power...