Powerful Workstations 2010

Power Sources Electromagnetic Spectrum Oscillators

SUBJECT: RADIO AM FM UNIT I

SO DOES THE ELECTROMAGNETIC SPECTRUM



RADIATION OF ELECTROMAGNETIC WAVES

oscillation or acceleration of any electrical charge generated a physical phenomenon consisting of electric and magnetic components, spectrum of radiation known as electromagnetic waves.

Fig. 1 full spectrum of radiation of electromagnetic waves.


That spectrum can be ordered from waves that have very low frequencies of a few hertz (Hz) or cycles per second with very long lengths, such as the frequency of the alternating current we use in our houses, until a very high frequency waves, thousands of millions of hertz or cycles per second with extremely short lengths, such as those with cosmic radiation.

The only difference between a wave group and others within the electromagnetic spectrum is the frequency in hertz (Hz), its length in meters (m) and transmit energy level in joules (J).

Main features of electromagnetic waves

The three main characteristics of the waves that constitute the electromagnetic spectrum are:

Frequency (f)

Length (λ)

Amplitude (A)


Frequency

The frequency of a wave corresponds to a physical phenomenon that is repeated cyclically a certain number of times for a second time, as shown in the following illustration:
fig. 2
A. - sine wave cycle or hertz (Hz) per second. B. - Sine wave of 10 cycles or hertz per second

The frequency of these waves of the electromagnetic spectrum are represented by the letter (f) and its unit of measurement is the cycle, or hertz (Hz) second.


wavelength

spectrum electromagnetic waves propagate through space in a similar way as water does when you throw a stone into a pond, that is, generating waves at the point where it falls the stone and extending to the shore.

When we throw a stone into a pond, waves are generated similar to
radiation characteristic of the electromagnetic spectrum.


Both waves are produced by displacement of water as the waves of the electromagnetic spectrum have peaks or ridges and valleys or bellies.

The horizontal distance between two consecutive peaks, two consecutive valleys, or even twice the distance between a node and other electromagnetic wave, measured in multiples or fractions of meters (m), constitutes what is called length wave. "

P. - Peak or crest: the maximum value of positive sign (+), takes the sine wave spectrum. electromagnetic, each half cycle, from the "0". This value increases or decreases as. amplitude "A" of the wave increases or decreases very positively over the value "0."

V. - Valle or womb maximum negative value (-), which takes the sine wave spectrum. electromagnetic, each half cycle, as it descends and crosses the "0". . The value of the valleys. increases or decreases as the amplitude "A" of the wave itself grows or decreases negatively. below the value "0."

T. - Period: time in seconds that elapses between the passage of two peaks or two valleys for the same. point.

N. - Node: Value "0" of the sine wave.

a wave length of the electromagnetic spectrum is represented by the Greek letter lambda. (Λ) and its value can be found using the following mathematical formula:

Where:

λ = wavelength in meters.
c = speed of light in vacuum (300 000 km / sec.)
f = wave frequency in hertz (Hz).

For example, if we want to know what band in meters (SW) transmits a radio station that is captured in the 7.1 MHz frequency on the dial, proceed as follows:



The speed of light (300 000 km / sec) become m / sec, to get the final result in meters. This operation is performed as follows, taking into account that 1 km is equal to 1 000 meters:

300 000 km / sec x 1 000 m = 300 000 000 meters / sec



below the 7.1 megahertz are converted in hertz (Hz), which is the unit of measurement frequency, given that 1 MHz is equal to 106 Hz, or 1 million Hz: 7.1 MHz x

106 = 7.1 x 1 000 000 = 7 100 000 Hz (or 7.1 million cycles per second)



The result of these two conversions substitute their values \u200b\u200bin the above formula and we have: Therefore
, the wavelength of the signal of 7.1 MHz will be 42.2 meters per cycle or hertz frequency. This length corresponds to the range of short wave radio (OC) that respond to the band corresponding range of 41 meters in the face of a receiver.


Wavelength

The amplitude is the maximum value that can reach the crest or peak of a wave. The point of less value received the name of the valley or belly, while the point where the value vanishes in passing, is known as "node" or "zero."

properties of electromagnetic waves

for its propagation of electromagnetic waves do not require a specific material medium, it can travel even outer space.

electromagnetic waves, as mentioned above, are spread by the vacuum at the speed of light (300 000 km / sec approximately), until your energy runs out. As the frequency increases, the wave energy increases.

This type of wave has the same physical properties
wave motion inherent



Research: Mr. Ricardo Arreola Navarro

January 2008 CETIS 58

Subject: Radio AM FM

Zachery Tims Pregnacy

Vetusta Morla. Essential




Summary: Vetusta Morla was the giant tortoise The Neverending Story, do not ask me again, because I have not seen the film. Hence
these locals took their name back in the late 90's. Its six components are tired of winning championships junior group and after two EPs, they uncover with their first full length published just yesterday. Lyrics full of meaning, drink the purest britpop.
Discography: Squaring the circle (demo) 2003 # Mira (EP) 2005 # One day in the World 2008.
Media: New Single
.



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French Stone Oven Blueprints

Subject: RADIO UNIT I

BASIC PRINCIPLES OF SWING

The definition of rock is fluctuating between two states and conditions:

Swinging is vibrating or change from one state to another state.

An oscillator is a device that produce oscillations in the form of repetitive waves.

An oscillator is an electronic circuit used in electronic communications as frequency generator to transmit signals between a transmitter and a receiver.


an oscillator in electronic applications is a device or circuit that produces oscillations power.

A power swing is a repetitive change of voltage or current waveform.

If an oscillator is self sustained, changes in the waveform is continuous and repetitive.

A self-sustained oscillator circuit does not require a input signal for its operation, it is generating its own electronic signal.

can say that the only signal that is applied to an oscillator is a DC voltage (bias voltage) to operate.

An oscillator in an electronic circuit from a dc voltage generates a voltage as BC sine wave.



2 .- OSCILLATORS FEEDBACKS

oscillators to function properly must have a feedback loop.

feedback in electronic means take a portion of the output signal and return to the entrance.

Figure 1 shows an example of the principle of feedback.

feedback is to send a voltage or current output to the input.

Fig. 1 Model of a feedback amplifier

The feedback loop is physically an electrical connection made by a cable.

electronics exist in two types of feedback:

Feedback

positive negative feedback


In oscillator circuits using the positive feedback.

There are four requirements that must be met to achieve a good performance in an oscillator:

1.1 .- Amplification: an oscillator must have an amplifier capable of amplifying voltage.

1.2 .- Positive feedback: An oscillator circuit must have a complete path for the output signal back to the entrance.

feedback signal must be regenerated, that means that you must have the correct phase and amplitude correct. (*) 1.3 .-

to determine the frequency components: An oscillator must determine the frequency components such as resistors, capacitors, coils or crystals that allow to set or change the operating frequency. 1.4 .-

Power: An oscillator to operate like any other electronic circuit requires a power supply.

To produce self-sustained oscillations, an oscillator circuit must meet four basic requirements described above.

The most common configurations used in an oscillator for its operation are: RC (Resistance-Capacitor)
LC (coil-capacitor), the quartz crystals and integrated circuits.


3 .- TANK CIRCUIT

In an electronic oscillator which aim is to obtain an oscillating system which is stable and regular, maintaining a frequency and a continuous waveform.

This natural process takes advantage of possessing the damped oscillation circuits composed of elements capacitive or inductive .

These elements have the ability to store electrical charge inside (electrically charged) and unloaded when the load of food has gone.

The simplest example of oscillator is composed of a coil, a capacitor, a battery and a switch.

This circuit is called tank circuit.

Figure 2 describes the tank circuit

Tank circuit
Fig. 2

Initially the switch is left in place so that the capacitor C is charged with providing battery power V.

After some time the switch is passed to the right position. As the coil has no load and the capacitor is fully charged, the latter is fully discharged into the coil, once the capacitor is completely discharged now winding which is downloaded onto the
capacitor, not standing until the load on the coil is zero and therefore the capacitor is again charged.

This process is repeated until the stored energy is consumed either as heat.

This process can be plotted using an XY Cartesian axis in the x-axis represents time and the y-axis value of the electric current flowing through the coil and the voltage at the terminals of the capacitor.

If you draw it we can see how there is a continuous exchange of energy between the capacitor and coil.

The subtraction of energy produced by the resistance of the inductor and capacitor (which can overheat the components) is what makes this process is not infinite.

Fig. 3 curves LC oscillator

In the graph we can see how the gap voltage between terminals of the coil is always in effect opposite to that in the condenser.

This lag is 180 ° between strains, there is a gap of 90 ° between the current flowing through the coil and tension.

This signal is buffered to the time until become extinct after a relatively short time period. An electronic circuit that is capable of reloading electrically one component will make a consistent swing
process.

oscillation frequency

The characteristic of this type of circuit, also known as LC tank circuit is that the speed with which current flows and returns from the condenser coil or vice versa, occurs with a frequency

(F) itself, often called resonance, which depends on the values capacitor (C) and coil (L), and is given by the following formula:
where:

F is measured in Hertz, C in Farads and L in henry .

All Small And Mighty Buy

[6].


Simple Minds.

Summary: Scottish rock band, standard bearer of the New Wave movement. Outstanding movement in the decade of 80. Although originally started playing in late 70's, coming from other bands closest to punk styles , was undoubtedly his most poppy twist what they took by storm the charts around the world.
probably more than one @, having danced remember any of their successes. Although his first and best known hit is Do not You (Forget About Me) and I stay in my essential Theme For Great Cities. Alfredo sure remember this topic as input from a television program.

Media: Theme For Great Cities.

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Engravable Charm Bracelets Winnipeg

Soul / Funk


Nicole Willis & The Soul Investigators.

Summary: Lead American who has collaborated with musicians from very different styles like electronic music or black music. Married with Jimi Tenor.
started his career in London back in 84, accompanying some of the future components of The Brand New Heavies. His first solo record is edited in 2000. Later, in 2004, came her second album. In 2005, in collaboration with the Finnish group The Soul Investigators, would his third job. A disc retro soul and funk. Interestingly most international success comes at the end of 2007 with the reissue of the third disc in the form of remixes.

Discography: Soul Makeover, it Bee 2000 #, 2004 # Keep Reachin 'up, 2005 # Keep Reachin' Up Remixes, 2007.

Media: I left you a comparison of two versions of one song star disc.

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