A photodetector is a device that imprints the image of an object or scene onto a material. Photodetectors are made in various ways and can be used for different purposes. Most photodetectors fall into the phototube, thermal detector, or camera category. These photodetectors are used for communication, navigation, and record keeping. Types of Photodetectors Phototube …
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 …
In order to deter theft, the majority of major automobile manufacturers implement a car radio security code. When the car stereo is removed from a vehicle, the device will not be usable until the unlock or security code is entered by the car owner or authorized repair facility. Unfortunately, some models of cars and trucks …
A retrograde orbit is an orbit where the satellite travels in an East to West direction instead of the common West to East orbit. The normal West to East orbits are known as prograde orbits. Retrograde orbits are uncommon due to the much higher velocities necessary for successful launch and the associated higher costs. During …
Electromagnetic Interference (EMI) most commonly occurs in the 104 to 1012 Hertz frequency range of the electromagnetic spectrum. A number of sources create this interference, including radio transmitters, electric motors, power lines, fluorescent lights, and computer circuits. If electrical equipment do not have suitable EMI shielding in place, device failure may result from the interference …
Crosstalk is a form of interference caused by signals in nearby conductors. The most common example is hearing an unwanted conversation on the telephone. Crosstalk can also occur in radios, televisions, networking equipment, and even electric guitars. Causes of Crosstalk Crosstalk is caused by coupling, the transfer of electrical energy between conductors. The three main …
Azimuth is a measurement at an angle used in the spherical coordinate system. To find a point of interest, the observer creates a vector that is then projected in a perpendicular fashion onto a reference plane. The resulting angle between the projected vector and the reference vector located on the reference plane is the azimuth. …
Standing Wave Ratio (SWR) meters are used to measure the standing wave ratio in a communications transmission line. The meter can display how much a transmission line and the load are mismatched (normally a radio antenna). It also determines how effective the impedance is of matching efforts. In CB and ham radio circles, the SWR …
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 …
dBm is the standard unit of measure for levels of power based on a one milliwatt (mW) reference signal. The dBm measurement is very similar to dB (decibel); however, dB is a relative measure of the power of an input signal while dBm is always an absolute value based on a single milliwatt. If there …