Basic Electronics 2

ACOUSTICS

Branch of Physics that is concerned with production, control, transmission, reception and effects of sound.

SOUND

A mechanical energy that repetitively causes collisions of molecules in a medium,

AMPLITUDE OF PRESSURE CHANGES

Described by the maximum amplitude, or the root-mean-square (P_RMS) amplitude and is expressed in Pascal (Pa). 

DECIBEL

Unit used to measure the intensity or loudness of a sound.

FREQUENCY

Number of compressions or rarefactions per second. 

PERIOD

The time taken for one cycle of a wave to pass a fixed point, measured in second. 

WAVELENGTH

Distance travelled by the pressure wave during one cycle

MICROPHONES

Device that converts sound signal into an electrical signal.

SOUND LEVEL METERS

Used to assess noise or sound levels by measuring sound pressure.

FREQUENCY SPECTRUM ANALYZERS

Measures the magnitude of an input signal vs. frequency within the full frequency range.

SOUND PRESSURE

Force of sound on a surface area  perpendicular to the 

direction of the sound, is also called acoustic pressure.

TRANSMISSION

A method of sound propagation where a signal travels in a straight line from the source to the destination

REFLECTION

A signal is reflected, leading to echoes.

REFRACTION

A signal moves from one medium to another. There is a change in velocity, frequency and wavelength.

DIFFRACTION

A sound wave moves around an object whose dimensions are smaller or equal to the wavelength of the sound

ABSORPTION

A part of a wave is transformed to heat and is transmitted through the absorbing body.

SCATTERING

A signal is reflected in different directions

AIRBORNE NOISE

A source of noise where soundwaves transmitted from a source to a receiver through the air

STRUCTURE-BORNE NOISE

Caused by vibration within the building caused by footsteps or machines.

AMPLIFIER

A device that increases the amplitude of an audio signal.

MICROPHONE

It is a transducer

PRE-AMPLIFIER

Converts a weak electrical signal into an output signal strong enough to be noise-tolerant and for processing or sending to a power amplifier and a loudspeaker.

POWER AMPLIFIER

Designed to increase the magnitude of power of a given input signal.

BIPOLAR JUNCTION TRANSISTOR / BJT

Derived from “transfer resistor” means resistance is changed. 

EMITTER

Supplies the charge carriers (electrons in NPN, holes in PNP) into the base.

BASE

Lightly doped region between the emitter and collector.

COLLECTOR

Collects the charge carriers that have traveled across the base.

CAPACITIVE REACTANCE

Is the opposition to the flow of current offered by the capacitor, measured in ohms.

DIVIDING NETWORK

Also called the crossover network. A circuit that separates the range of frequencies in an audio signal into two or more parts so each part may be delivered.

PASSIVE TYPE DIVIDING NETWORK

A component or group of components that is installed on the speaker wires between an amplifier and a speaker.

ACTIVE DIVIDING NETWORK

Modifies the audio signal before the amplifier. Therefore, it is connected before the amplifier.

TV TRANSMITTER

Sends audio and video signals from a source, such as a cable box, computer, or streaming device, to a display.

TV RECEIVER

Captures signals and converts into a format that can be displayed on a screen.