Cost

Since each instrument returned for reconditioning must receive individual attention, the work must be handled in much the same way as a special manufacturing job. Consequently, the amount of supervision required per instrument is considerably more than that necessary in reg ularly scheduled production. An analysis of the performance characteristics must be made as well as a schedule of mechanical repairs. All badly worn or defective parts must be replaced, resistance elements readjusted, and...

The Megohm Bridge

IT IS BECOMING of increasing importance to be able to measure accurately and rapidly high resistances in the range from 1 megohm to 1,000,000 megohms. The volume resistivity of insulating materials is a fundamental property in predicting their electrical characteristics. It is particularly sensitive to small traces of moisture and so becomes a valuable measure of moisture content. When this property is used in conjunction with dielectric constant and power factor, a powerful means is offered...

Mr Ireland To New York

Smith for the West Coast, Mr. Frederick Ireland takes charge of the New York office. Mr. Ireland has been a member of our engineering staff for several years, coming to us from Harvard University, where he was a member of the Class of 1933. Having spent a considerable amount of time at the New York office in the last few years, he is already well known to General Radio customers in the New York district. HHHE General Radio EXPERIMENTER is mailed without charge each...

Building Precision Into An Air Condenser

Precision Condenser

IN TECHNICAL FIELDS, uni-versai acceptance for a product does not depend on ballyhoo, but can result only from recognized excellence. This quality has made General Radio precision condensers the standard of capacitance for the electrical-communications industry. The life span of the well-known Type 222 Precision Condenser 1919-1936 is traceable directly to the excellence of the original design plus a full utilization of advances in materials and manufacturing methods. A good condenser in 1919...

Miscellany

Gilman joined the Engineering Department of the General Radio Company. Mr. Gil-man receives his S.M. degree in electrical engineering from M.I.T. in June of this year. ON APRIL 20, R. F. Field spoke before the Pittsburgh section of the I.R.E. on the subject of Direct-Reading Instruments.'1 He plans to deliver this paper before the Indianapolis section on May 13. FOR SEVERAL MONTHS, Arnold Peterson of M.I.T. has been engaged in a research project at General Radio Company...

Mr Smith Goes To Hollywood

To 988 General Radio customers on the Pacific Coast went, last month, cards announcing the opening of a Los Angeles engineering and sales office on December 1. Mr. Myron T. Smith, who takes over the new office, will be available for consultation concerning the application of General Radio instruments. Mr. Smith lias been in charge of our New York office since its establishment several years ago. Prior to that time he was a member of the factory engineering staff, coming to us shortly after...

Test Instrument

The Type 732-A Distortion and Noise Meter has been designed to measure the combined harmonic distortion at 400 cycles. In practice it is loosely coupled to the output stages of the transmitter, preferably to the antenna loading coil or one of its as The Class 730-A Transmission Monitoring Assembly installed at WNAC. The operator is shown using the Type 731-A Modulation Monitor. The Type 732-A Distortion and Noise The Class 730-A Transmission Monitoring Assembly installed at WNAC. The operator...

Scale Disc

Scale Disc

Speed adjusted until the A ring is stationary. The disc can be illuminated by means of a neon lamp connected to the output of a vacuum-tube amplifier. A d-c bias on the lamp is usually required to prevent flashing at double frequency. When the pitch to be measured is produced by a musical instrument, a microphone is necessary as well. In using this disc,it should be remembered that it represents the intervals of the diatonic scale only, and not those of the tempered scale used on a piano. The...

Meter

The indicator is a large high-speed Weston Model 643 Meter. The needle reaches its maximum deflection in approximately 0.15 second wrhich means that it will respond to the shortest pulses occurring in most speech and music circuits. The mechanical damping This instrument has been developed in collaboration with the Columbia Broadcasting System. Their assistance in design and testing is gratefully acknowledged. stops the swing at maximum amplitude with no appreciable overshoot, and an electrical...

The Measurement Of Mutual Inductance

Mutual Inductivity

Of the most important properties of electrical circuits. By means of it the world's power is transmuted from generator voltage to transmission line voltage and back to the voltage suitable for our motors and electric lights. Yet the measurement of mutual inductance is of little importance as compared to measurements of self-inductance, capacitance, and resistance. The major reason for this slighting of mutual inductance lies in the interesting fact that iron-core transformers are nearly...