A circulator is a box-shaped ferrite device that has three or four ports and allows energy from one port to transfer to the next port in line. Circulators are usually used with radio signals but can also be used with microwaves, light, and other electromagnetic waves. This means that a radio signal that is being emitted from a transmitter in port one travels to an antenna in port two and then to a receiver in port three. Any residual energy in the receiver is eventually transferred back to port one. Read More

Pulse position modulation is a signal modulation technique that allows computers to share data by measuring the time each data packet takes to reach the computer. It is often used in optical communication, such as fiber optics, in which there is little multi-pathway interference. Pulse position modulation exclusively transfers digital signals and cannot be used with analog systems. It transfers simple data and is not effective at transferring files. How Pulse Position Modulation Works Pulse position modulation works by sending electrical, electromagnetic, or optical pulses to a computer or other Read More

The volt is the standard unit of voltage. It is defined as the electric potential difference required to move one ampere of current through a conductor with one ohm of resistance. According to Ohm's law, one watt of power is used, which is released as heat and warms the conductor. An analogy to voltage is water pressure. Water will only move between two points if there is a difference in pressure between them. A volt is basically a unit amount of extra force. History of the Volt The volt was Read More

Linear amplifiers are electronic circuits that have an output that is proportional to the input of the device while providing additional power to the load. A linear amplifier is normally a variant of a radio-frequency (RF) power amplifier and is used frequently in amateur radio and in laboratory and commercial audio equipment with an output measured in watts and kilowatts. How Do Linear Amplifiers Work? Linear amplifiers can either be based on vacuum tube or solid state technology. Most of the commercially produced devices for amateur radio still use vacuum Read More

Backward Error Correction, also known as an “Automatic Repeat Request” is an error correction technique in which a receiving device sends a request to the source device to re-send information. Backward Error Correction is used in situations where some of the transmitted data has been lost or corrupted during transit and the transmitting device must resend the information in order for the receiving device to understand the transmission. Backward Error Correction is the opposite of “Forward Error Correction”, in which a transmitting device simply sends redundant information to make up Read More

A ground loop isolator prevents interference in a ground loop circuit. A ground loop circuit is one in which two or more circuits are connected to the same ground wire. Ideally, all circuits in a ground loop circuit have the same voltage potential. However, if the ground wire has significant resistance and current, the voltage of the second circuit will be slightly lower than the first, causing a voltage difference that makes the ground wire no longer have a ground potential. This is known as interference and can be hazardous, Read More

A Weber is the standard unit of magnetic flux. It is defined as the magnetic flux needed to produce one volt of electromagnetic force in one turn of wire, when the flux is constantly reduced to zero over a period of one second. The symbol for weber is Wb. History of the Weber The Weber was first defined at an international conference in 1881, and is named after Wilhelm Eduard Weber (1804-1891), a German physicist. It was later amended in 1933 to it's current definition. Measuring Webers The strength and Read More

An infrared sensor is a device that emits and/or receives infrared waves in the form of heat. While most infrared sensors transmit and receive infrared waves, some can only receive them. These types of infrared sensors are known as Passive Infrared Sensors (PIR sensors) or motion detectors. What is an Infrared Detector? An infrared detector is a pyroelectric sensor that detects the light spectrum’s infrared wavelength. Infrared detectors are usually emitters as well, but this is not always the case. Infrared detectors can be made of a phototransistor, photodiode, or Read More

More properly known as the Bayonet Neill-Concelman connector, the BNC connector is one of several radio frequency connectors on the market today. The name of the connector is derived from a combination of two things: 1) the connecting technology employed; and 2) the names of the two inventors of the device. Paul Neill of Bell Labs and Carl Concelman sought to develop a connector that would employ a bayonet mount mechanism for locking. Building on the research of Octavio M. Salati, the two men perfected an earlier design and created Read More

A ground, also called an earth, is a source of unlimited charge that remains at zero volts. It is the point from which all other potential differences in a circuit are measured, and can be used as the return path for current in a circuit. Mains Power Ground Each building will usually have a long metal rod driven into the soil that is connected to all the ground wires in the building. If a fault occur, the current is suppose to flow through the ground wires instead of the body, Read More