Dear viewers,
In this post
we are going to see some basic electronic terms & definitions, Radio
Frequencies that used in Radio Astronomy and also in day-to-day electronic life
cycle. These reference will help the
readers and other public to understand the basic of electronics and frequency
range that is used in practical life. This reference may not contain all the
electrical terms, it contains only the very few basic and familiar terms of
electronic life.
Note:
The definitions
and names used in post are their scientific names. I haven’t used any local
names and also these definitions are took from Google. I want to convey my credits to all the sites
who helped me to write this post. All these terms and definitions are
overview only they have not given very depth.
i.)
Frequency Range and Purpose:-
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Frequency band
|
Designation
|
Radio astronomy use
|
|
13.36 - 13.41 MHz
|
HF
|
|
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25.55 - 25.67 MHz
|
HF
|
|
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37.5 - 38.25 MHz
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VHF
|
Continuum observations
|
|
73 - 74.6 MHz
|
VHF
|
1. Solar wind
observations.
|
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2. Continuum observations.
|
||
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150.05 - 153 MHz
|
VHF
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1. Continuum
observations.
|
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2. Pulsar
observations.
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3. Solar observations.
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322 - 328.6 MHz
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UHF
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1. Continuum
observations.
|
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2. VLBI
|
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406.1 - 410 MHz
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UHF
|
1. Continuum
observations.
|
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2. Pulsar
observations.
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608 - 614 MHz
|
UHF
|
1. Continuum
observations.
|
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2. VLBI
|
||
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1400 - 1427 MHz
|
L-band
|
Spectral line observations
|
|
1660 - 1660.5 MHz
|
L-band
|
VLBI
|
|
1660.5 - 1668.4 MHz
|
L-band
|
1. VLBI
|
|
2. Line observations.
|
||
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3. Continuum
observations.
|
||
|
1668.4 - 1670 MHz
|
L-band
|
Continuum observations
|
|
1718.8 - 1722.2 MHz
|
L-band
|
|
|
2655 - 2690 MHz
|
S-band
|
|
|
2690 - 2700 MHz
|
S-band
|
|
|
3260 - 3267 MHz
|
S-band
|
|
|
3332 - 3339 MHz
|
S-band
|
|
|
3345.8 - 3352.5 MHz
|
S-band
|
|
|
4800 - 4990 MHz
|
C-band
|
|
|
4990 - 5000 MHz
|
C-band
|
1. Continuum
observations.
|
|
2. VLBI
|
||
|
5000 - 5030 MHz
|
C-band
|
VLBI
|
|
6650 - 6675.2 MHz
|
C-band
|
1. Continuum
observations.
|
|
10.6 - 10.68 GHz
|
X-band
|
1. Continuum
meausurements.
|
|
2. VLBI
|
|
Frequency band
|
Designation
|
Radio astronomy use
|
|
10.68 - 10.7 GHz
|
X-band
|
1. Continuum observations.
|
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2. VLBI
|
||
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14.47 - 14.5 GHz
|
Ku-band
|
1. Spectral line
observations.
|
|
2. VLBI
|
||
|
15.2 - 15.35 GHz
|
Ku-band
|
VLBI
|
|
15.35 - 15.4 GHz
|
Ku-band
|
1. Continuum
observations.
|
|
2. VLBI
|
||
|
22.01 - 22.21 GHz
|
Ka-band
|
Spectral line observations
|
|
22.21 - 22.5 GHz
|
Ka-band
|
Spectral line observations
|
|
22.91 - 22.86 GHz
|
Ka-band
|
Spectral line observations
|
|
23.07 - 23.12 GHz
|
Ka-band
|
Spectral line observations
|
|
23.6 - 24.0 GHz
|
Ka-band
|
1. Spectral line
observations
|
|
2. Continuum
observations
|
||
|
31.2 - 31.3 GHz
|
Ka-band
|
Continuum observations
|
|
31.3 - 31.5 GHz
|
Ka-band
|
Continuum observations
|
|
31.5 - 31.8 GHz
|
Ka-band
|
Continuum observations
|
|
36.43 - 36.5 GHz
|
Ka-band
|
Spectral line observations
|
|
42.5 - 43.5 GHz
|
Q-band
|
Spectral line observations
|
|
48.94 - 49.04 GHz
|
Q-band
|
Spectral line observations
|
|
51.4 - 54.25 GHz
|
V-band
|
|
|
58.2 - 59 GHz
|
V-band
|
|
|
72.77 - 72.91 GHz
|
V-band
|
Spectral line observations
|
|
86 - 92 GHz
|
W-band
|
1. Spectral line
observations.
|
|
2. Continuum
obserations.
|
||
|
92 - 94 GHz
|
Spectral line observations.
|
|
|
95 - 100 GHz
|
1. Spectral line
observations.
|
|
|
2. Continuum
observations.
|
ii.) Basic Electric Terms and Definitions:-
Alternating Current (ac):-
Current from a power source that changes polarity periodically.
Alternator:-
A device that supplies
alternating current.
Ammeter:-
An instrument used for
measuring current.
Ampacity:-
The current–carrying
capacity of conductors in amperes.
Amperage (A):-
The amount of electric
current in amperes.
Ampere (A):-
The unit of measurement
for current. One ampere is that current whereby one coulomb of charge passes
through a point in one second. Named for André Ampere.
Ampere-hour (Ah) :-
Unit of measurement for
cell or battery capacity. One Ah generally means that a current of
one amp has been flowing for one hour.
Amplifier:-
An electronic circuit
that boost the voltage and/or the current level of a signal.
Analog:-
Generally refers to
signals that have many discrete values versus digital binary signal that have
only two states. Also, refers to the branch of electronics dealing with such
signals and their circuits. The term linear is another term often used
for such circuits and signals.
Analog-to-digital converter (A/D) :-
A circuit or devise
used to convert an analog signal to a digital form.
Cable:-
A stranded conductor or
group of individual conductors insulated from each other.
Capacitance (C) :-
The ability of two
conductors separated by an insulator to store an electrical charge, measure in
farads (F).
Capacitor:-
A device designed to
provide a specific amount of capacitance.
Circuit:-
An arrangement or
connection of circuit devices and components to perform a specific
objective. In the simplest form it would require an energy source, a load
to transform the energy into the desired task, and conductors to connect the
source to the load. In most applications a control device (switch) would
be included and may also include a protective device. Common example of a
simple circuit would be a flashlight.
Circuit breaker:-
A circuit protection
device that opens the circuit automatically when an overload or short circuit
occurs.
Coil:-
A wound spiral of two
or more turns of insulated wire, used to introduce inductance into a circuit,
produce a magnetic field from current flow, or to respond to a changing
magnetic field by producing a voltage or mechanical motion.
Component/s:-
In electronics, a general term to refer to a part or parts of
a circuit without reference to specific names.
Conductance (G) :-
The ability of a
conductor to allow the flow of electrons. Measured in Siemens (S). The
reciprocal of resistance.
Conductor:-
A low-resistance
material to provide a path for current. Used to interconnect components
in a circuit.
Conventional current:-
A direction flow
assignment that has current flowing from positive to negative.
Current (I) :-
The rate of flow of
electrons through a conductor or component; measured in amperes. The
symbol (I) stands for intensity of the electron flow.
Cycle:-
One complete wave of
alternating voltage or current.
Digital:-
Generally in
electronics, refers to signals, devices, or circuits that are binary, meaning
they only have two states (high or low, 1 or 0, on or off). The branch of
electronics dealing with such signals and their circuits.
Digital-to-analog converter (D/A) :-
A circuit that converts
a binary signal to an equivalent analog form.
Direct Current (dc) :-
Current from a power
source that continually flows in the same direction. An electrical
source of constant polarity.
Electric energy:-
The energy carried by
free electrons from a source to a load. Also, the potential energy of a
stationary charge.
Electric power (P) :-
The rate at which
energy is consumed in a circuit or load. Measured in watts (W).
Electromotive Force (emf) :-
The force or electrical
pressure that has the potential to cause electron flow in a circuit. Also
called voltage, potential difference or difference of potential. Measured
in volts (V).
Electrostatic field:-
An electric field
produced by stationary charges.
Frequency:-
The number of cycles
per second for a periodic waveform. Measured in hertz (Hz).
Fuse:-
A protective device
designed to interrupt current flow (open) through a circuit when current
exceeds a rated value.
Heat sink:-
A device attached to a
component to aid in the dissipation of heat.
Hertz (Hz) :-
A unit of frequency
equal to one cycle per second. Named for Heinrich Hertz, a German
physicist who was the first to produce radio waves artificially.
Impedance (Z) :-
Opposition to current
flow from the combined effects of resistance and reactance measured in ohms
(S).
Inductance (L) :-
The property of a
circuit that opposes a change in current. Also, the property of a circuit to
store energy in the form of a magnetic field and release it back into the
circuit at a later time.
Inductor:-
An electrical device
designed to provide a specific amount of inductance; measured in henrys (H).
Insulation:-
Nonconductive material
used to cover wires and components to prevent shock and short circuits.
Insulator:-
A material that has a
high resistance to current flow.
Integrated Circuit (IC) :-
The placement of
numerous components and circuits on to a silicon chip.
Internal resistance:-
The resistance within a
power source.
Inverter:-
A logic devise (NOT
function) whose output is always opposite the input. Also refers to
a devise that converts dc to ac.
Load:-
A device or apparatus
that uses the energy of a circuit to perform work. May also refer to the
power used by a device, machine, or a combination of many.
Magnet:-
An object which
produces a magnetic field in the surrounding space.
Magnetic field:-
The detectable magnetic
flux issuing from a magnet or electromagnet.
Multimeter:-
An instrument that can
measure current, voltage, and resistance on various ranges. Many
multimeters can measure other circuit values such as frequency and
capacitance. May have digital (DMM) or analog displays (VOM).
Ohm (S) :-
The unit of measurement
for resistance. Named for Georg Simon Ohm, the German physicist noted for his
contributions to mathematics, acoustics, and the measurement of electrical
resistance. One ohm is that resistance that limits the current to one
ampere when a potential of one volt exist across its terminals.
Ohmmeter:-
An instrument for
measuring resistance.
Oscillator:-
A circuit that converts
dc power into ac signals with constant frequency. Also, an instrument
that generates ac signals whose frequency and amplitude can be
varied. These are also referred to as signal generators.
Oscilloscope:-
An instrument that
displays a plot of voltage over time. Often referred to as a scope.
Overload:-
A load in excess of the design limit for
a circuit.
Polarity:-
For
electrical charge, the indication of a charge as either positive (+) or
negative (-). Voltage at a point would be indicated as being either
positive or negative with respect to some other point. For magnetic
poles, the indication as either north or south.
Potentiometer:-
A three-terminal
resistor with an adjustable center connection generally used to control
voltage; widely used for volume control in radio and television receivers. In
this sense, also called a Pot.
Resistance (R) :-
The opposition to
current flow in a circuit; measured in ohms.
Resistor:-
An electrical component
designed to provide a specific resistance. Available in many formats such
as fixed, tapped, and variable. See potentiometer and rheostat.
Secondary winding:-
The output winding of a
transformer or one of several output windings.
Short circuit:-
An undesirable low
resistance path between two points in a circuit.
Solid-state:-
The term that describes
components or circuits that use semiconductors technology.
Stepper motor:-
A motor type driven
with digital codes that moves in discrete angular increments with each code
change.
Surge:-
A very rapid increase
of current or voltage.
Switch:-
A device used to open
(turn off) and close (turn on) electrical circuits that can be designed to operate
by numerous actions such as toggle, slide, and pushbutton actions. Standard
configurations include SPST, SPDT, DPST, and DPDT.
Transducer:-
A device used to
convert input energy of one form into output energy of another.
Transformer:-
A device used to transfer
electric energy from one circuit to another, especially a pair of multiply
wound, inductively coupled wire coils that effect such a transfer with a change
in voltage, current, phase, or other electric characteristic. Generally used to
convert one voltage-current relationship to another. Step-up transformer,
increase the voltage while decreasing the current, and step-down transformer
decrease the voltage while increasing the current.
Transistor:-
A small electronic
semiconductor device having at least three electrical contacts, used in a
circuit as an amplifier or a switch. See: BJT, JFET, MOSFET.
True power:-
The actual power
consumed by a circuit; measured in watts.
Volt (V) :-
The unit by which an
electromotive force or voltage is measured. Named for Alessandro Volta, the
Italian physicist who invented the first electric battery (1800).
Voltage (V) :-
Same as emf. The
force or electrical pressure that has the potential to cause electron flow in a
circuit.
Voltage divider:-
A series circuit that
divides voltage.
Voltage drop:-
The difference in
potential between two points caused by current flow through a component.
Voltmeter:-
An instrument used to
measure voltage.
Watt (W) :-
The unit of measurement
for power. One watt equals to the work done when one joule is used per
second. Named for James Watt the British engineer and inventor.
Watt-hour (Wh) :-
Unit of energy consumed
at the rate of one watt (W) for a time of one hour. Equivalent to 3,600
joules.
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