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 typically used as a diagnostic step when troubleshooting potential electrical issues. What Can a Multimeter Do? You will see multimeters that are both digital and analog with each type providing similar data that can be Read More

A battery isolator is used to prevent primary battery systems from being drained and are mostly used in car stereo systems. These devices cause a secondary/auxiliary battery to be drained instead of the vehicle’s primary battery. This is so whether the stereo is used when the engine is turned off or if an after-market stereo system has been installed that requires more power than the stock vehicle battery can provide. Types of Battery Isolators There are two types of battery isolators: solenoid (relay) and diode. Diode Battery Isolators The diode Read More

An amplifier uses a small input signal to create a large output signal, while minimizing distortion of the waveform. Amplifiers are used for both electrical and optical signals. Working of an Amplifier Modern amplifiers use solid-state electronics, although some are still made with vacuum tubes. A basic amplifier can be made with transistors, while complex amplifiers use other components, like op-amps, for feedback correction. To reduce the electrical noise, most amplifiers use toroidal transformers for their power supply. Features of an Amplifier The important features of an amplifier are its Read More

Wiring a light switch–whether because you need a new one or are adding new light switches to a house–is a process that requires some basic understanding of how a light switch works. To begin with, you need to make sure you’ve got the wiring all through the house. Once you have the wiring and can access them, wiring a light switch shouldn’t take much longer than a few minutes. Wiring a Light Switch To begin with, ensure that power to the switch is turned off. To do this, trip the Read More

A dBm is a standard unit for measuring levels of power in relation to a 1 milliwatt reference signal. dBm is similar to dB, or decibel, except that where dB is relative to the power of the input signal, dBm always relates to a 1 milliwatt signal. In other words, dB is a relative measurement and dBm is an absolute measurement. A minus sign before the dBm indicates a loss and a plus sign or no sign at all before the dBm indicates a gain. The dBm Formula The dBm Read More

Fixed Satellite Service (FSS) is a type of mobile telephone service that allows users in a specific area to make and receive cell phone calls. FSS systems or cell phone towers are placed in strategic, fixed locations and provide service to thousands of individual users simultaneously. Generally, FSS systems provide reception for several square miles around them, which borders another FSS system’s reception area. This allows users to communicate with multiple FSS systems as they travel without losing reception.   How Fixed Satellite Service Works FSS systems are essentially large Read More

A polar orbit is an orbit of any object in space, natural or synthetic, that passes around the Earth in a North-to-South direction rather than a West to East direction, which is known as an “equatorial orbit”. Polar orbits are advantageous because they will eventually travel across every possible latitudinal and longitudinal position on the Earth, allowing satellites that depend on a polar orbit to monitor the Earth much better than any other type of orbiting satellite.   How Polar Orbit Works Polar-orbiting satellites are launched in the same way Read More

MSK (Minimum Shift Keying) is a type of continuous frequency shift modulation that is used to transfer radio signals from satellites and radio broadcasting to mobile devices and vice versa. Unlike other forms of frequency modulation, MSK produces a half sine wave that limits problems associated with non-linear distortion. What is GMSK? GMSK (Gaussian Minimum Shift Keying) is a type of MSK that uses the same basic concepts, but applies a Gaussian filter to a signal before its frequency is modulated. A Gaussian filter uses a square wave to shape Read More

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 the carrier and the modulating signal to generate an amplitude modulated signal. The nonlinear device’s output consists of discrete upper and lower sidebands. A nonlinear device’s output does not vary in direct proportion with the Read More

A microphone is an electromechanical device that uses vibration to create an electrical signal proportional to the vibration, which is usually an air pressure wave. There are many different types of microphone, ranging from the old condensers to the modern piezoelectrics. Microphone History Alexander Graham Bell invented the first microphone in 1876 as part of the telephone. Thomas Edison invented the first carbon microphone in 1886, a significant improvement on Bell’s impractical liquid microphone, and the forerunner of the modern microphone. Microphone Types Condenser microphones are a capacitor that has Read More