A multivibrator is a device that changes between two states and its own design or an external force powers it. For example, a weight that is placed on a suspended spring will extend the spring to its maximum length as gravity weighs down on it. When the spring is stretched to its maximum length, however, …
Geostationary satellites are located exactly above the earth’s equator and revolve around the earth in a circular orbit. Their revolving speed and direction (west to east) are exactly same as that of the earth, which makes it look stationary from the earth’s surface. The exact altitude of these satellites above the equator is approximately 36,000 …
An integrated circuit (IC), also called a microchip, is an electronic circuit etched onto a silicon chip. Their main advantages are low cost, low power, high performance, and very small size. History The integrated circuit was invented in 1958 by Jack Kirby (1923-2005), an American engineer. In 2000, he won the Nobel prize in physics …
A PID (Proportional Integral Derivative) controller is a device that makes changes to a system based on current and intended settings. PID controllers are used in a wide variety of industrial control systems and are the most commonly used feedback controllers in the world. PID controllers allow users to obtain and/or maintain preferred conditions within …
A relay is a remote switch controlled by current, magnetism, or temperature. The relay was invented in 1835 by Joseph Henry (1979-1878), an American scientist. Relays are a common component in many devices, and there are many different types of relays. Relay Types The two main types of relay are electromechanical and solid-state. Electromechanical relays …
VSWR (Voltage Standing Wave Ratio) is a metric commonly used with antenna systems for ham or shortwave radio communication. VSWR is normally defined as a ratio with a 1:1 VSWR, indicating that there is an exact or perfect match between all antenna system elements. The VSWR can also be expressed by comparing Vmax with Vmin …
A police scanner is basically a radio scanner that is also a receiver that receives wireless radio signals. A scanner identifies these wireless radio waves. A scanner can identify numerous radio signals and bands concurrently making it easy to keep track of many channels simultaneously. The phrase “police scanner” derives from the fact that the …
Voltage is the measurement for the electrical force between two points that drives the current. More specifically, voltage is the measure of the energy per unit charge that is equal to the electrical potential difference between two measured points. Volts are normally measured by a voltmeter. Voltage drop is the reduction in voltage in an …
A photoresistor is a light-dependent resistor which slowly loses its resistance when exposed to high levels of ultraviolet light. As a result, photoresistors convert light energy into electrical energy. Photoresistors are used in a wide variety of devices to detect the presence of light, control a device, or activate a system. They are usually dependent …
Resistors can come in different sizes and shapes allowing for different voltages to go through it. However, unless the size of the resistor is large, the code is rarely written on it because it would require very tiny markings. Therefore, a system was developed to use colors to determine the resistor code. In other words, …