A rheostat is an electrical component that has an adjustable resistance. It is a type of potentiometer that has two terminals instead of three. The two main types of rheostat are the rotary and slider. The symbol for a rheostat is a resistor symbol with an arrow diagonally across it. Rheostats are used in many …
Satellite images were initially the exclusive realm of military and government agencies. They then became commercially available at very steep prices. Technology has now improved to the point where satellite images are available so inexpensively that they are now provided for free online. Free Satellite Images on the Web The best and by far the …
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 …
A multimeter is used to take measurements of electrical properties for a circuit such as the voltage, current, or resistance. A modern multimeter combines the abilities of legacy voltmeters, ohmmeters, and ammeters. Some of the uses of a multimeter include electrical testing on electrical power sources, motors, and other electrical circuits or components. They are …
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 …
A Butterworth filter is a signal processing filter that has an extremely flat frequency response in the passband. It is referred to as a maximally flat magnitude filter and is commonly used in both analog and digital audio crossover filters in home, commercial, and car stereo systems. Who Invented the Butterworth Filter? British engineer, Stephen …
A solid state relay is a device that controls voltage to allow or prevent a voltage or current from passing through a circuit without using any moving parts. Solid state relays are commonly found in control systems that use large amounts of power and must be switched on and off on a regular basis. Solid …
An Internet repeater is a device that allows amateur radio operators to communicate with each other over the Internet, much like how VoIP software allows telephone operators to communicate with each other over the Internet. Internet repeaters should not be confused with wireless repeaters, which allow users to extend the range of a wireless network. …
Anyone planning to work on electronics or automobiles that have been manufactured in the past decade, need to be able to use a digital multimeter. Modern multimeters contain three measuring devices in one: an ammeter, voltmeter, and ohmmeter. The top section of the device contains the digital read out and it can be viewed in …
Amplitude modulation is a type of modulation where the carrier signal’s amplitude is varied in accordance with the information bearing signal. The amplitude modulated signal’s envelope or boundary embeds the information bearing signal. The total power of the transmitted signal varies with the modulating signal, whereas the carrier power remains constant. A nonlinear device combines …