Description

An elementary schematic diagram of the Type 71G-P4 Guard Circuit is shown in Figure 3, as connected to a Type 716-C Capacitance Bridge, also shown in elementary form. The guard circuit proper consists of a set of resistive arms (corresponding to S and T in the general network of Figure 3. Elementary schematic circuit diagram of the Type 716-P4 Guard Circuit connected to the Type 716-C Capacitance Bridge. Figure 1) one of which is a fixed resistor, the other variable, consisting of a pair of...

S

Cross-section diagrams of the Type 874-WN3 Short-Circuit Termination and the Type 874-W03 Open-Circuit Termination. can be readily computed or compensated. The Type 874-M Component Mount has been designed with these objectives in mind. It provides a shielded enclosure of convenient size within which a component can be mounted in a variety of ways, thereby enabling the user to approximate a circuit environment closely. Mounted on a Type 874-B Coaxial Connector, it connects to a Type...

Types Wo And Wn Open And Shortcircuit Terminations

These units, which are furnished as accessories with the Type 874-M Component Mount and the Type 874-UB Balun, are available separately. They present an open or short circuit at a point exactly 3 cm. beyond the face of the bead in the Type 874 Connector. As lias been mentioned before, this distance corresponds to the distance between the connector bead and the ground plane in the Type 874-M Component Mount and the distance between the connector bead and the unbalanced terminals in the Type...

Circuit

The instrument uses a cathode-coupled 1-Mc crystal oscillator. While the circuit is not new, it is somewhat unconventional. The first half of the twin triode operates Q S cathode follower, while the second half is a grounded-grid amplifier. The plate circuit of the amplifier is tuned to 1 Mc, and the voltage appearing across the tuned circuit is fed back to the grid of the cathode follower, thus completing the oscillating circuit. The germanium diode in the plate circuit of the cathode follower...

Miscellany

Richmond, Chairman of the Board, General Radio Company, to Life Membership of the Corporation of the Massachusetts Institute of Technology. CONGRATULATIONS to Seyffer and Co., A.G., exclusive distributors of General Radio products in Switzerland, who this year are celebrating the 30th anniversary of the founding of their company. Our pleasant association with this firm and its officers began in 1939. RECENT VISITORS FROM OVERSEAS Jacques Bendayan, Chief, Telecommunication...

The Type U B Balun

The Type 874-UB Balun brings to the measurement of balanced impedances the simple, accurate techniques already highly developed for coaxial systems. The need for measurements of this kind is growing rapidly with the use of balanced systems in television and communications, and satisfactory equipment has not previously been available. For accurate impedance measurements, it has generally been found impractical to use conventional transformers to effect the conversion from balanced to unbalanced...

Type Lk Constantimpedance Adjustable Line

Measurements on 50-ohm coaxial systems can be greatly facilitated if the lengths of transmission lines in the system can be adjusted without introducing appreciable discontinuities. It is usually not possible to measure impedance directly at the location of an unknown, because some length of line exists between the point at which the measurement is made and the point at which it is desired. This line length may be a piece of coaxial cable necessary to connect the measuring instrument to an...

General Radio Company

Genrad 938 Binding Post

275 MASSACHUSETTS AVENUE CAMBRIDGE 39 MASSACHUSETTS NEW YORK 6, NEW YORK LOS ANGELES 38. CALIFORNIA CHICAGO 5. ILLINOIS 90 WEST STREET 1 000 NORTH SEWARD STREET 9 20 SOUTH MICHIGAN AVENUE TEL. WOrth 2 -58 37 T E L. H 0 I ly w o o d 9 -620 1 TEL. WAbash 2-3820 STANDARDIZED TERMINALS AND CONNECTORS STANDARDIZED TERMINALS AND CONNECTORS the name of General Radio has been identified with high quality standard parts. The Type 274 Banana Plug, originally designed as an improvement over earlier...

The Vacuumtube Bridge And Its Accessories

THE TYPE 561-D VACUUM-TUBE BRIDGE, first described twenty years ago,1 is used for measuring directly the vacuum-tube coefficients of amplification factor, transconductance, and plate resistance. Not a tube tester, the bridge is a laboratory-type instrument of high accuracy that permits a study of tube performance at widely varying operating conditions. The method devised by Tuttle2 substitutes accurately known and controlled individual voltage sources of low internal impedance for the...

New Comparison Bridge For The Rapid Testing Of Components

THE TREND toward complexity and more exacting specifications in electronic equipment has been accompanied by a tremendous increase in the quantities produced, and, as a result, more and more precise components resistors, capacitors, and inductors are being used. In general, it is necessary to measure these components before assembly, and this measurement, particularly for 1 per cent or 0.25 per cent components, is usually made on a laboratory-type bridge. As the number of components to be...

Note On The Singleended Pushpull Amplifier

Much interest has been shown in the article on the push-pull amplifier circuit in the October, 1951, issue of the Experimenter. Some of our correspondents have cited earlier work in which series-con-nected output tubes have been used. Since others may also be interested, we reproduce here their combined references, all of which are U. S. Patents. A study of these patents appears to show that none of them have anticipated the basic circuit of Figure I of the October, 1951, Experimenter, which is...

Type A Soundlevel Meter

A Miniaturized and Improved Basic Instrument for Sound and Noise Measurements THE SOUND-LEVEL METER is the basic instrument of a sound measuring system. Born in the '30's as a result of the joint effort of several technical societies interested in standardizing acoustic noise measurements, its uses have grown constantly as man's environment has become noisier. Expanding uses inevitably condition the development of a product, and so the first General Radio Sound-Level Meter, Type 759-A 1936 was...

Delivery Schedules

The heavy demands for the rearmament program of the United States and our allies have given us at General Radio a real job to do. As most of our readers know, it takes time to produce precision equipment. The process of manufacturing it is not the kind that can be speeded up quickly to meet increased demand rather, the production growth is a slow and careful process if quality, accuracy, and satisfactory long-life performance are not to be impaired. The problem is further complicated by the...

Western Instrument Company Offers Repair Service To West Coast Customers

West Coast users of General Radio instruments can now have their equipment repaired and recalibrated in California, thus avoiding the expense and delay that now occur when material is returned to our factory. Western Instrument Company, 826 North Victory Boulevard, Burbank, California, has been appointed West Coast service agency for General Radio products. This firm has a well-equipped laboratory and machine shop to give prompt and competent repair service on all General Radio instruments....

Threequarter Horsepower Variac Motor Speed Control

Variac Motor Controller

Uses of Vaeiacs in Electrical Engineering Power Western Instrument Company Offers Repair Service to West Coast Customers. . 7 third horsepower rating of insufficient for this duty, although it has proved ample for many special applications such as toroidal winding machines, resistance-card-winding machines, and for lathes used in finishing small parts. It has been apparent that a unit of about three-quarter horsepower rating THE VARIAC SPEED CONTROL provides adjustable-speed operation of d-c...

Quiet Ship

The United States Lines' new record-breaking ocean liner, gt S lt S United States, is said to be remarkably quiet. To prove this, a General Radio pocket-size Sound-Survey Meter went along on the trial runs, to compare sound levels in the various spaces of the ship. Trial runs are short and time is limited, but Gibbs and Cox, Inc., the naval architects who designed the ship, found that with the The SS United States, new holder of the Atlantic blue ribbon, has attained speeds of 35.59 knots on...

Type X Insertion Unit

This unit is a hollow cylinder fitted with Type 874 Connectors at each end. Its cover sleeve slides back to allow ac- cess to a region inside of about 2 inches in length and He inch in diameter. In this region between the Type 874 Connectors, almost any arbitrary arrangement of small components, such as resistors, capacitors, or inductors, can be mounted. The insertion unit, shown in Figure 20, has been used as a shielded housing for impedance matching networks, attenuator pads, YHF...

New Adaptors For The Vacuumtube Bridge Sub Miniature Types Now Available

2g21 Circuit

Although the fundamental circuit has remained unchanged since the first Type 561-A Vacuum-Tube Bridge was designed, the mechanism for connecting the tube into the circuit has required considerable modification. The original bridge had 4-, 5-, 6-, and 7-pin sockets on the panel with provision for connecting other types through binding posts.2 An 8-pin socket was added later, but, as the list of tube bases grew, it became evident that the panel socket system would eventually be inadequate. In...

More Useful Variac Circuits

The note entitled A Useful Variac Circuit, appearing in our August issue, has evoked letters from readers who have used similar but still more useful circuits. Mr. G. M. Brown, Electronics Engineer for the New York Central System, offers the circuit of Figure 1, which includes a manual switch to give control over a 245-volt range. A similar circuit was submitted by Mr. G. D. Stark of Allis-Chalmers Manufacturing Company. Mr. J. H. Odenheimer, Plant Engineer, Switchgear Department, General...

Third Conference On Highfrequency Measurements

Under the joint sponsorship of AIEE, IRE, and the National Bureau of Standards, the Third Conference on High-Frequency Measurements will be held in Washington on January 14-16, 1953. This conference will follow the pattern of similar meetings held in 1949 and 1951 and will be devoted exclusively to the techniques and problems of high-frequency measurements, with particular emphasis on new developments. RECENT VISITORS to the General Radio plant and laboratories include Mr. Carl Schr der of the...

Calibrationcheck Service For Sound Meters

Our Sales and Engineering Offices in Cambridge, New York City, Chicago, and Los Angeles now offer a new, free service to owners of General Radio Sound-Level Meters and Sound-Survey Meters in those areas. When circumstances of a measurement problem call for assurance, or reassurance, that results be highly accurate, or when a possible calibration error is indicated or suspected, it is desirable to check the over-all calibration of the instrument in question. An accurate yet simple check can be...

Megacycle Schering Bridge

Capacitor Testing Schering Bridge

Both commercial and military specifications on capacitors of 1000 nnf and less call for measurements of capacitance and dissipation factor at a frequency of one megacycle. Similarly, the grading of insulating materials is often based on the measured dielectric constant and loss factor at one megacycle. While the Type 916-A Radio-Frequency Bridge and the Type 821-A Twin-T are capable of making such measurements, neither instrument is ideal for the purpose. The Type 916 does not offer the desired...

The Soundsurvey Meter

Sound Level Calibrator Design Circuit

A Simple, Pocket-Size Instrument for Noise-Level Measurements A Note on the Single-Ended Push-Pull MANY SOUND M E A S U R EM E N TS do not require the accuracy and versatility of a standard sound-level meter and many others are economically feasible only with a low-cost meter. For these applications, the Type 1555-A Sound-Survey Meter, shown in Figure 1, has been developed. It is similar in operating characteristics to the standard sound-level meter and is comparable in accuracy, stability, and...

1

IN PART F of this article, the design and the features of the Type 938 series of binding posts were discussed. Another important type of terminal is the jack, designed to accept a banana plug, and typified by the Type 274-J Jack, which has been the industry standard for some 25 years. Not only are these jacks useful for making connections between various points with leads terminating in Type 274-DB Insulated Single Plugs and Type 274-MB Double Plugs, but they serve as excellent...

New Coaxial Accessories Adaptors Line Stretcher Component Mount Balun Terminations And Insertion Unit

Line Stretcher

EARLY IN THE DEVELOPMENT OF RADAR, the importance of smooth coaxial connections became evident, and coaxial measuring equipment was found necessary to achieve them. The virtues of completely shielded structures with uniformly distributed parameters and simple geometric configurations were quickly recognized, and a tremendous effort was put forward to bring coaxial measurement techniques up to a level adequate for accurate measurement. Out of this work came widespread use of the slotted line,...