- Type 546-0, Audio-Frequency Microvolter
- Type 716-C, Capacitance Bridge
- Type 805-C, Signal Generator
- Type 1540 Strobolume, a professional grade stroboscope
Company type | Public |
---|---|
NYSE: GEN | |
Industry | |
Founded | June 14, 1915 [1] : 8 in Cambridge, Massachusetts, US |
Founder | Melville Eastham |
Defunct | October 27, 2001 [1] : 240–241 |
Fate | Merger |
Successors |
|
Headquarters | |
Key people | James Kilton Clapp |
Number of employees | 1,524 (2001) |
Website | genrad.com at the Wayback Machine (archived 29 February 2000) |
General Radio Company (later, GenRad) was a broad-line manufacturer of electronic test equipment in Massachusetts, U.S. from 1915 to 2001.
On June 14, 1915, Melville Eastham and a small group of investors started General Radio Company in Cambridge, Massachusetts, a few blocks northwest of Massachusetts Institute of Technology. [2] During the 1950s, the company moved to West Concord, Massachusetts, where it became a major player in the automatic test equipment (ATE) business, manufacturing a line of testers for assembled printed circuit boards. It also produced extensive lines of electrical component measuring equipment, sound and vibration measurement and RLC standards. In 1975, the company name was changed to GenRad.
In 1991, a startup QuadTech [3] was founded as spinoff of GenRad's Instrumentation division and Precision Product lines, as well as the rights to use the "GenRad" and "General Radio" names. In 2000, IET Labs [4] acquired from QuadTech the GenRad RLC standards, impedance decades, megohmmeters, digibridges, audio lines, stroboscope lines. Then in 2005 IET Labs purchased the Digibridge and Megohmmeter lines, which continue to be manufactured in West Roxbury, Massachusetts. In 2001, Teradyne acquired the GenRad board test system lines, which were relocated to Teradyne's corporate campus in North Reading, Massachusetts. [1] : 240–241
Among General Radio's accomplishments over the years have been:
An operational amplifier is a DC-coupled electronic voltage amplifier with a differential input, a (usually) single-ended output, and an extremely high gain. Its name comes from its original use of performing mathematical operations in analog computers.
A multimeter is a measuring instrument that can measure multiple electrical properties. A typical multimeter can measure voltage, resistance, and current, in which case can be used as a voltmeter, ohmmeter, and ammeter. Some feature the measurement of additional properties such as temperature and capacitance.
The characteristic impedance or surge impedance (usually written Z0) of a uniform transmission line is the ratio of the amplitudes of voltage and current of a wave travelling in one direction along the line in the absence of reflections in the other direction. Equivalently, it can be defined as the input impedance of a transmission line when its length is infinite. Characteristic impedance is determined by the geometry and materials of the transmission line and, for a uniform line, is not dependent on its length. The SI unit of characteristic impedance is the ohm.
In electrical engineering, electrical length is a dimensionless parameter equal to the physical length of an electrical conductor such as a cable or wire, divided by the wavelength of alternating current at a given frequency traveling through the conductor. In other words, it is the length of the conductor measured in wavelengths. It can alternately be expressed as an angle, in radians or degrees, equal to the phase shift the alternating current experiences traveling through the conductor.
In electrical engineering, a transmission line is a specialized cable or other structure designed to conduct electromagnetic waves in a contained manner. The term applies when the conductors are long enough that the wave nature of the transmission must be taken into account. This applies especially to radio-frequency engineering because the short wavelengths mean that wave phenomena arise over very short distances. However, the theory of transmission lines was historically developed to explain phenomena on very long telegraph lines, especially submarine telegraph cables.
A waveguide is a structure that guides waves by restricting the transmission of energy to one direction. Common types of waveguides include acoustic waveguides which direct sound, optical waveguides which direct light, and radio-frequency waveguides which direct electromagnetic waves other than light like radio waves.
Coaxial cable, or coax, is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric ; many coaxial cables also have a protective outer sheath or jacket. The term coaxial refers to the inner conductor and the outer shield sharing a geometric axis.
Phillip Hagar Smith was an American electrical engineer, who became famous for his invention of the Smith chart.
Analog Devices, Inc. (ADI), also known simply as Analog, is an American multinational semiconductor company specializing in data conversion, signal processing, and power management technology, headquartered in Wilmington, Massachusetts.
Amphenol Corporation is an American producer of electronic and fiber optic connectors, cable and interconnect systems such as coaxial cables. Amphenol is a portmanteau from the corporation's original name, American Phenolic Corp.
Teradyne, Inc. is an American automatic test equipment (ATE) designer and manufacturer based in North Reading, Massachusetts. Its high-profile customers include Samsung, Qualcomm, Intel, Analog Devices, Texas Instruments and IBM.
A capacitance multiplier is designed to make a capacitor function like a much larger capacitor. This can be achieved in at least two ways.
RG-59/U is a specific type of coaxial cable, often used for low-power video and RF signal connections. The cable has a characteristic impedance of 75 ohms, and a capacitance of around 20pF/ft (60pF/m). The 75 ohm impedance matches a dipole antenna in free space. RG was originally a unit indicator for bulk radio frequency (RF) cable in the U.S. military's Joint Electronics Type Designation System. The suffix /U means for general utility use. The number 59 was assigned sequentially. The RG unit indicator is no longer part of the JETDS system (MIL-STD-196E) and cable sold today under the RG-59 label does not necessarily meet military specifications.
In electronics, a Lecher line or Lecher wires is a pair of parallel wires or rods that were used to measure the wavelength of radio waves, mainly at VHF, UHF and microwave frequencies. They form a short length of balanced transmission line. When attached to a source of radio-frequency power such as a radio transmitter, the radio waves form standing waves along their length. By sliding a conductive bar that bridges the two wires along their length, the length of the waves can be physically measured. Austrian physicist Ernst Lecher, improving on techniques used by Oliver Lodge and Heinrich Hertz, developed this method of measuring wavelength around 1888. Lecher lines were used as frequency measuring devices until inexpensive frequency counters became available after World War 2. They were also used as components, often called "resonant stubs", in VHF, UHF and microwave radio equipment such as transmitters, radar sets, and television sets, serving as tank circuits, filters, and impedance-matching devices. They are used at frequencies between HF/VHF, where lumped components are used, and UHF/SHF, where resonant cavities are more practical.
Melville Eastham was a noted American radio pioneer and business executive.
An LCR meter is a type of electronic test equipment used to measure the inductance (L), capacitance (C), and resistance (R) of an electronic component. In the simpler versions of this instrument the impedance was measured internally and converted for display to the corresponding capacitance or inductance value. Readings should be reasonably accurate if the capacitor or inductor device under test does not have a significant resistive component of impedance. More advanced designs measure true inductance or capacitance, as well as the equivalent series resistance of capacitors and the Q factor of inductive components.
Nominal impedance in electrical engineering and audio engineering refers to the approximate designed impedance of an electrical circuit or device. The term is applied in a number of different fields, most often being encountered in respect of:
An RLC circuit is an electrical circuit consisting of a resistor (R), an inductor (L), and a capacitor (C), connected in series or in parallel. The name of the circuit is derived from the letters that are used to denote the constituent components of this circuit, where the sequence of the components may vary from RLC.
Performance modelling is the abstraction of a real system into a simplified representation to enable the prediction of performance. The creation of a model can provide insight into how a proposed or actual system will or does work. This can, however, point towards different things to people belonging to different fields of work.
Arthur Oswin Austin was an American electrical engineer and inventor. He is the inventor of the Austin transformer, a double-ring toroidal transformer used to supply power for lighting circuits on radio towers. Austin's research included improvements to radio transmission equipment and the effects of lightning on high-voltage transmission lines and aircraft. He was a fellow of the American Institute of Electrical Engineers and of the Institute of Radio Engineers, and was an expert in high-voltage insulators and fittings. His work on transmitting antennas included both military and civilian projects.
QuadTech was established in March of 1991 with the purchase of the Precision Instrument Division of GenRad. The products and people joining QuadTech from GenRad at that time represented a long and successful heritage going back to 1915 when GenRad was founded.
In 2000, IET Labs acquired the GenRad standards, impedance decades, megohmmeters, digibridges, audio and strobe lines and now continues to manufacture, service and support these.