Over 10,000 tons of sulfur hexafluoride (SF6) are produced annually, most for use as a gaseous dielectric material. It is a high-value alternative to oil and air in circuit breakers and switchgear. SF6 is an extremely robust insulator. It consists of six fluorine atoms bonded in an octahedral configuration to a central sulfur atom. The […]
What are integrated gas spacer cables
Basics of induction
Building on the work of others, particularly Humphry Davy, Hans Christian Ørsted and Alessandro Volta, English researcher Michael Faraday formulated his Law of Electromagnetic Induction. This most basic of all laws governing electromagnetism quantifies the interaction of a magnetic field and an electric circuit, producing electromotive force (EMF) or in the language of technicians and […]
Basics of metal detectors
The sensor assembly of a metal detector consists of one or more coils, usually two. An oscillator outputs an alternating current that passes through the send coil, producing a fluctuating magnetic field that penetrates the ground or other layer that is opaque to visible light. The fluctuating magnetic field induces eddy currents in any conductive […]
Basics of cloud chambers
A tabletop cloud chamber is a simple home project that can be built, and can detect and display condensation trails that develop in the presence of ionizing radiation. It was invented by Charles Wilson, who perfected a working model in 1911. For many decades it was used by researchers and it played an important role […]
Basics of the Global Positioning System
The Global Positioning System (GPS) evolved from earlier relatively primitive systems that were originally developed primarily for military uses. Before long these systems became available worldwide for civilians but at reduced resolution. Then in 1996 President Bill Clinton signed a document that had the effect of ending selective availability. Today GPS at maximum resolution can […]
The Doppler effect in EM and cellular phones
Prior to 1800 the Doppler Effect was unknown because there weren’t speeding railroad trains or motorized fire trucks with blaring sirens, so the phenomenon was outside of human experience. The first person to take note of the Doppler Effect and after whom it was named was an Austrian, Christian Doppler. He had poor health and […]
Basics of aircraft electrical systems
Electrical design in aircraft is influenced by two basic requirements: The equipment must be light weight and highly reliable. These needs may be met in a variety of ways. At inception, electrical parameters are chosen to minimize weight so the aircraft can get off the ground with its payload and gain altitude without expending unnecessary […]
Basics of setting up electrical service in buildings
Any building or electrical installation must have an electrical service unless it has an onsite power supply or connects via feeder to some other installation that itself has a service. Requirements and definitions reside in National Electrical Code (NEC) article 230, Services. It defines an electrical service as the part of the installation from the […]
Where does the noise floor come from?
In an audio or video receiver or in any type of measuring instrument, noise may be defined as any signal other than the one of interest. In the display of an auto-ranging oscilloscope, it is manifest as an irregular horizontal trace not far above the X-axis. There are many sources of noise, both human-made and […]
Sizing up networks with pinging
Pinging is the process whereby we send an exploratory probe or packet consisting of 64 bytes or more to a network node. It contains a return request and takes its name from the analogous pulse of sound sent and received by a sonar installation. When this burst of data is returned, certain information becomes available […]