Basic diodes are constructed from two semiconductor materials, germanium or silicon, to create a basic PN-junction. When two single diodes are connected to each other back-to-back, two PN-junctions that are connected in series are created. They share a common N or P terminal, which forms the basis of a BJT or Bipolar Junction Transistor. The …
The SMA (SubMiniature Type A) connector is a type of the radio frequency connector developed in the 1960s to make it easier to connect coaxial cables. Using a screw-type design instead of the common ‘push-pull’ system, the SMA connector allows for a quick connection; and can be used in both alternating and direct current applications. …
Satellite images are taken by reconnaissance satellites that orbit the Earth at a relatively low altitude, between 300 to 600 miles (or 480 to 970 km). As the majority of today's satellites are custom made in order to accommodate particular needs of the designer, there is no standard on which photo imagery is based on …
A common question asked by new student of electronics is what is a momentary switch? The short answer is that a momentary switch is a unit capable of turning any electronic device to either an on or off state when an end-user presses the switch. This type of switch can actually represent one of two …
Downlink is a term in telecommunications that is used to refer to a data transmission in which data flows from an orbital satellite receiver to a ground-based transmitter. Downlink transmissions rely on the C Band between 3.7 and 4.2 GHz, the Ku Band between 11.7 and 12.7 GHz, and the Ka Band between 18.3 and …
An isolation transformer is made of two copper coils that are wound around each other and are each supplied by their own power source. While the term “isolation transformer” technically refers to any transformer, it is specifically a transformer that isolates a circuit from an alternating current. An isolation transformer does this by separating two …
An attic antenna is one that is mounted inside of an attic in order to provide maximum range as well as protection from rain, snow, sun, wind, and animals. Attic antennas are rather common and provide quality reception for those who live in rural areas, away from most radio transmitters. While attic antennas do not …
An opto isolator is an electronic device that prevents high voltages from components in one side of a circuit from damaging or interfering with components on the other side of the same circuit. Opto isolators regulate voltage levels by converting electricity into a beam of light. This prevents voltage spikes from impacting more than a single …
Portable radios are limited in the power at which they can transmit, usually somewhere between .5 watts and 5 watts. A very rough rule of thumb is that one watt equals one mile of range over flat and open terrain. Buildings and mountains will, of course, greatly modify effective range. When two radios communicate directly …
A fractal antenna is a diamond-shaped antenna that maximizes the total amount of material within a given amount of space that transmits or receives electromagnetic waves. Fractal antennas do this by making each section of the antenna its own separate dipole. Because of this design, fractal antennas operate at many different frequencies and wavebands, allowing …