Selasa, 20 September 2011

Dual section air variable capacitor

Dual section air variable capacitor
was invented to provide tracking between two related LC-tuned circuits, as in a radio receiver. Such capacitors are basically two (in the case of Fig. 5) or more variable capacitors mechanically ganged on the same rotor shaft.

In Fig. 5, both sections of the variable capacitor have the same capacitance, so they are identical to each other. If this capacitor is used in a superheterodyne radio, the section used for the local oscillator (LO) tuning must be padded with a series capacitance in order to reduce the overall capacitance. This trick is done to permit the higher-frequency LO to track with the RF amplifiers on the dial.

In many superheterodyne radios, you will find variable tuning capacitors in which one section (usually the front section) has fewer plates than the other section. One section tunes the RF amplifier of the radio, and the other tunes the local oscillator. These capacitors are sometimes called cut-plate capacitors because the LO section plates are cut to permit tracking of the LO with the RF.
READ MORE - Dual section air variable capacitor

Transmitting air variable capacitor

Transmitting air variable capacitor
Differential variable capacitors also have two independent stators, but unlike in the butterfly capacitor where capacities on both sides increase equally as the rotor is turned, in a differential variable capacitor one section's capacity will increase while the other section's decreases, keeping the stator-to-stator capacitance constant. Differential variable capacitors can therefore be used in capacitive potentiometric circuits.

The one requirement of transmitting variable capacitors (and certain antenna tuning capacitors) is the ability to withstand high voltages. The high-power ham radio or AM broadcast transmitter will have a dc potential of 1500 to 7500 V on the RF amplifier anode, depending on the type of tube used. If amplitude-modulated,the potential can double. Also, if certain antenna defects arise, then the RF voltages in the circuit can rise quite high. As a result, the variable capacitor used in the final amplifier anode circuit must be able to withstand these potentials.
Two forms of transmitting variables are typically used in RF power amplifiers and antenna tuners. Figure 7 shows a transmitting air variable capacitor. The shaft of this particular capacitor is nylon, so it can be mounted either with the frame grounded or with the frame floating at high voltage. The other form of transmitting variable is the vacuum variable. This type of capacitor is a variation of the piston capacitor, but it has a vacuum dielectric (K factor = 1.0000). The model shown in Fig. 8 is a 18- to 1000-pF model that is driven from a 12-Vdc electric motor. Other vacuum variables are manually driven.

Vacuum variable capacitor
READ MORE - Transmitting air variable capacitor

phase locked loop (PLL)

"Digital phase-locked loop block diagram"

A phase detector compares two input signals and produces an error signal which is proportional to their phase difference. The error signal is then low-pass filtered and used to drive a VCO which creates an output phase. The output is fed through an optional divider back to the input of the system, producing a negative feedback loop. If the output phase drifts, the error signal will increase, driving the VCO phase in the opposite direction so as to reduce the error. Thus the output phase is locked to the phase at the other input. This input is called the reference.

Analog phase locked loops are generally built with an analog phase detector, low pass filter and VCO placed in a negative feedback configuration. A digital phase locked loop uses a digital phase detector; it may also have a divider in the feedback path or in the reference path, or both, in order to make the PLL's output signal frequency a rational multiple of the reference frequency. A non-integer multiple of the reference frequency can also be created by replacing the simple divide-by-N counter in the feedback path with a programmable pulse swallowing counter. This technique is usually referred to as a fractional-N synthesizer or fractional-N PLL

Typically, the reference clock enters the chip and drives a phase locked loop (PLL), which then drives the system's clock distribution. The clock distribution is usually balanced so that the clock arrives at every endpoint simultaneously. One of those endpoints is the PLL's feedback input. The function of the PLL is to compare the distributed clock to the incoming reference clock, and vary the phase and frequency of its output until the reference and feedback clocks are phase and frequency matched.

PLLs are ubiquitous—they tune clocks in systems several feet across, as well as clocks in small portions of individual chips. Sometimes the reference clock may not actually be a pure clock at all, but rather a data stream with enough transitions that the PLL is able to recover a regular clock from that stream. Sometimes the reference clock is the same frequency as the clock driven through the clock distribution, other times the distributed clock may be some rational multiple of the reference.

One desirable property of all PLLs is that the reference and feedback clock edges be brought into very close alignment. The average difference in time between the phases of the two signals when the PLL has achieved lock is called the static phase offset (also called the steady-state phase error). The variance between these phases is called tracking jitter. Ideally, the static phase offset should be zero, and the tracking jitter should be as low as possible.[dubious – discuss]

Phase noise is another type of jitter observed in PLLs, and is caused by the oscillator itself and by elements used in the oscillator's frequency control circuit. Some technologies are known to perform better than others in this regard. The best digital PLLs are constructed with emitter-coupled logic (ECL) elements, at the expense of high power consumption. To keep phase noise low in PLL circuits, it is best to avoid saturating logic families such as transistor-transistor logic (TTL) or CMOS.[citation needed]

Another desirable property of all PLLs is that the phase and frequency of the generated clock be unaffected by rapid changes in the voltages of the power and ground supply lines, as well as the voltage of the substrate on which the PLL circuits are fabricated. This is called substrate and supply noise rejection. The higher the noise rejection, the better.

To further improve the phase noise of the output, an injection locked oscillator can be employed following the VCO in the PLL.
Frequency Synthesis

In digital wireless communication systems (GSM, CDMA etc.), PLLs are used to provide the local oscillator for up-conversion during transmission and down-conversion during reception. In most cellular handsets this function has been largely integrated into a single integrated circuit to reduce the cost and size of the handset. However, due to the high performance required of base station terminals, the transmission and reception circuits are built with discrete components to achieve the levels of performance required. GSM local oscillator modules are typically built with a frequency synthesizer integrated circuit and discrete resonator VCOs.
READ MORE - phase locked loop (PLL)

AC contactor

LC1-D series AC contactor (simplified as contactor in the following)is suitable for using in the circuits up to the rated voltage 660V AC 50Hz or 60Hz, rated current 95A, for making and breaking and frequent starting, controlling the AC motor. Combined with the auxiliary contact group, air delayer, machine interlocking device etc, it is combined into the delay contactor, mechanical interlocking contactor, dtar-delta starter, with the thermal realay, it is combined into the electromagnetic starter.
READ MORE - AC contactor


supercapacitor has a limited range of applications, advances in design might eventually expand the product’s utility. For example, researchers continue to develop and experiment with newer forms of dielectric materials, such as carbon nanotubes, polypyrrole, and barium titanate, which may improve capacitance and energy density. The concept of combining supercapacitors with alternative energy sources to replace car batteries has gained appeal within the current "green" movement, and several public transportation systems have created pilot trials for capacitor-run buses and trains. If these and other developments yield successful results, the electric double-layer capacitor may achieve greater functionality and gain a larger role within the energy industry.

Manufacturers evaluating various electrical sourcing options should examine the strengths and weaknesses unique to the double-layer format. A supercapacitor’s energy density ratio typically ranges between 0.5 and 10 Wh/kg (nominal voltage over weight), which is considerably higher than that of a standard capacitor. While this energy density is still relatively low compared to mainline batteries, such as the lithium-ion model, the supercapacitor’s power density far exceeds the level offered by its counterparts. Power density is contingent on a device’s rate of electrical charging and discharging, meaning that supercapacitors can both generate and distribute energy more quickly than most batteries.

In addition, supercapacitors stop charging when their capacity limit is reached, eliminating the need for detection units to prevent overcharging. Aside from its excellent power density, a supercapacitor also has high cycle efficiency and can undergo millions of charging sequences in its lifespan.

However, low energy density and low voltage tolerance limit the effectiveness of an individual double-layer capacitor as a storage unit, unless it is serially linked to a group of capacitors. Furthermore, the supercapacitor’s linear discharge method often prevents the full charge from being delivered, resulting in small but detrimental energy waste. The high rate of self-discharge (energy loss due to internal chemical reactions) is a similar concern. Supercapacitor controls and electronic switching equipment can also be complex, and typically necessitate workers with specialized operational skills.
READ MORE - supercapacitor

practical capacitor

A practical capacitor is not limited to two plates. As shown to the right, it is quite possible to place a number of plates in parallel and then connect alternate plates together. In addition, it is not necessary for the insulating material between plates to be air. Any insulating material will work, and some insulators have the effect of massively increasing the capacity of the resulting device to hold an electric charge. This ability is known generally as capacitance, and capacitors are rated according to their capacitance.

It is also unnecessary for the capacitor plates to be flat. Consider the figure below, which shows two "plates" of metal foil, interleaved with pieces of waxed paper (shown in yellow). This assembly can be rolled up to form a cylinder, with the edges of the foil extending from either end so they can be connected to the actual capacitor leads. The resulting package is small, light, rugged, and easy to use. It is also typically large enough to have its capacitance value printed on it numerically, although some small ones do still use color codes.

The schematic symbol for a capacitor, shown below and to the right of the rolled foil illustration, represents the two plates. The curved line specifically represents the outer foil when the capacitor is rolled into a cylinder as most of them are. This can become important when we start dealing with stray signals which might interfere with the desired behavior of a circuit (such as the "buzz" or "hum" you often hear in an AM radio when it is placed near fluorescent lighting). In these cases, the outer foil can sometimes act as a shield against such interference.
READ MORE - practical capacitor

Minggu, 18 September 2011

Voltage regulator serves

Rectifier circuit is good enough if its voltage ripple is small, but there are stability issues. If the voltage PLN up / down, then the output voltage will also rise / fall. As rectifier circuit above, if the flow the greater the voltage dc discharge was also dropped. For some applications a voltage change is quite annoying, so it requires the active component that can regulate the output voltage becomes stable.

Voltage regulator serves as a filter voltage to suit. Therefore, usually in a series of power supply then the voltage regulator IC is always used for stable voltage outputan.

Here the composition of the regulator IC legs.

For example 7805 is a voltage regulator to get a +5 volt, +12 volt voltage regulator 7812 and beyond. While the 79XX series is the 7905 and 7912 such that a row is a voltage regulator -5 and -12 volts.

Apart from a fixed voltage regulators have a voltage regulator ICs also can be arranged. The principle is the same as the OP-amp regulator packaged in a single IC for regulators such as LM317 LM337 variable positive and negative variables for the regulator. The difference resistors R1 and R2 are outside the IC, so the output voltage can be set via external resistors.

The most simple regulator circuit shown in Figure 6. In this circuit, the zener breakdown work on the area, thus producing the same output voltage with a zener or a voltage Vout = Vi. However, this circuit is only useful if the load current not exceeding 50mA.
The principle that the power supply circuit is called a shunt regulator, one of his trademark is the component parallel to the load regulator. Another feature of the shunt regulator is susceptible to short-circuit. Notice when Vout connected short (short-circuit) then the current is fixed I = Vin/R1. In addition to a shunt regulator, there are also called series regulator. The main principle of such series regulator circuit in figure 7 below. In this circuit the output voltage is:

Vout = VZ + VBE

VBE is the base-emitter voltage of transistor Q1 which is between 0.2 - 0.7 volts depending on the type of transistor used. By ignoring the current IB flowing in the transistor base, a large resistance R2 can be calculated that is needed is:

R2 = (Vin - Vi) / Iz

Iz is the current minimum required by the zener diode to achieve the zener breakdown voltage. These large currents can be determined from the magnitude datasheet approximately 20 mA.

If necessary supply a larger current, base current IB of the calculations on the above circuit can not be ignored anymore. Where as it is known, a large flow of IC will be directly proportional to the flow defined by IB or IC = BIB. For this purpose, the transistor Q1 is used can be replaced with a Darlington transistor which typically has a value of b is large enough. With a Darlington transistor, the current small base that could produce a greater current IC.

Techniques that better regulation is to use the Op-Amp to drive a transistor Q, as in a series of figure 8. Zener diodes are not here to give direct feedback to the transistor Q, but as a reference voltage for the Op-amp IC1. Feedback on the negative pin of op-amp is an excerpt from the voltage regulator out, namely:

Vin (-) = (R2 / (R1 + R2)) Vout

If the voltage Vout rising out, the voltage Vin (-) will also be rising until the voltage is equal to the reference voltage Vi. And vice versa if the voltage Vout decreases exit, for example because of supply current to the load increases, the op-amp will maintain stability in Vi with a reference point to give the current IB to the transistor Q1. So at all times maintain the stability of the Op-amp:

Vin (-) = ½

By ignoring the VBE voltage of transistor Q1 and mensubsitusi formula (11) into the formula (10) of the obtained mathematical relationship:

Vout = ((R1 + R2) / R2) ½

In this circuit the output voltage can be set by adjusting R1 and R2 large.

Now it should no longer need to painstakingly search for the op-amp, transistors and other components to realize the regulator circuit as above. Because this kind of circuit has been packaged into a single fixed voltage regulator IC. Are now widely known as the 78XX series components of the voltage regulator to remain positive and 79XX series which is a voltage regulator to remain negative. In fact, these components are usually already equipped with current limiting (current limiter) and also limiting the temperature (thermal shutdown). This component is only three pins and by adding some components alone can be a series of power supply regulation was good.
READ MORE - Voltage regulator serves

semiconductor diode

Physical function
An LED is a special type of semiconductor diode.
Like a normal diode, an LED consists of a chip of semiconducting material is fully charged, or in-bulb, with impurities to create a structure called a pn junction.
-Charge carriers - electrons and holes flow into the junction from electrodes with different voltage.
When an electron meets a hole, he fell into a lower energy level, and release energy in the form of photons.

Light emission
The wavelength of light emitted, and therefore its color, depending on the difference in the energy band of the material that forms a pn junction.
A normal diode, typically made of silicon or germanium, emits visible light near infrared, but the material used for an LED have a difference between the energy band near infrared light, visible, and near ultraviolet.

Substrate LED
LED development began with infrared and red devices made with gallium arsenide.
Perkembagan in materials science have enabled the production of tools with shorter wavelengths, producing light with varied colors.

Conventional LEDs are made from inorganic mineral that varies, resulting in the following colors:
* Aluminum gallium arsenide (AlGaAs) - red and infrared
* Gallium aluminum phosphide - green
* Gallium arsenide / phosphide (GaAsP) - red, orange-red, orange, and yellow
* Gallium nitride (GaN) - green, pure green (or emerald green), and blue
* Gallium phosphide (GaP) - red, yellow, and green
* Zinc selenide (ZnSe) - blue
* Indium gallium nitride (InGaN) - turquoise and blue
Aluminum gallium indium phosphide * - orange-red, orange, yellow, and green
* Silicon carbide (SiC) - blue
* Diamond (C) - ultraviolet
* Silicon (Si) - blue (under development)
* Sapphire (Al2O3) - blue

Positive voltage phase of the first forwarded by D1, while the next phase which is passed through D2 to the load R1 with transformer CT as a common ground .. Thus the load R1 gets a full wave voltage supply like the picture above. For some applications such as for supply to a small dc motor or dc incandescent lamps, the shape of this voltage is sufficient. Although the voltage ripple seen here from the second series of the above is still very large.
series of half-wave rectifier with filter capacitor C is parallel to the load R. Apparently with this filter out the voltage waveform can be flat. Figure-4 shows a DC voltage output from circuit half-wave rectifier with capacitor filter. Bc line is approximately straight line with a certain slope, which in this state for the load current supplied by voltage capacitor R1. Actually the line bc is not a straight line but exponential in accordance with the nature of discharging the capacitor.
Bc depends on the slope of the curve of current (I) which flows to the load R. If the current I = 0 (no load) then the curve will form a horizontal line bc. But if the load currents greater, the slope of the curve bc will be more sharp. The voltage that comes out will be shaped with a sawtooth ripple voltage of magnitude are:


and dc voltage to the load is Vdc = VM + Vr / 2

A good rectifier circuit is a circuit that has a ripple voltage (Vr) the smallest. VL is the voltage discharge or discharge the capacitor C, so it can be written:

VL = VM e -T/RC

If equation (3) disubsitusi to formula (1), then diperole

VR = VM (1 - e -T/RC)

If T <

For example, you design a full wave rectifier circuit of the power supply 220V/50Hz grid to supply the load of 0.5 A. What is the value capacitors are necessary so that this circuit has a voltage ripple of not more than 0.75 Vpp. If the formula (7) turned upside down then obtained.

C = I.T / Vr = (0.5) (0.01) / 0.75 = 6600 UF

For capacitors that are widely available for elco type that has a maximum working voltage polarity and specific. Working voltage capacitors used must be greater than the power supply output voltage. You may now understand why you created a series of audio buzzing, trying to check the power supply rectifier circuit that you created, if the voltage ripple is quite disturbing. If the market is not available such a large capacitor, it could with two or three pieces paralel capacitor.
READ MORE - semiconductor diode

Light emission

Physical function
An LED is a special type of semiconductor diode.
Like a normal diode, an LED consists of a chip of semiconducting material is fully charged, or in-bulb, with impurities to create a structure called a pn junction.
-Charge carriers - electrons and holes flow into the junction from electrodes with different voltage.
When an electron meets a hole, he fell into a lower energy level, and release energy in the form of photons.

Light emission
The wavelength of light emitted, and therefore its color, depending on the difference in the energy band of the material that forms a pn junction.
A normal diode, typically made of silicon or germanium, emits visible light near infrared, but the material used for an LED have a difference between the energy band near infrared light, visible, and near ultraviolet.

Substrate LED
LED development began with infrared and red devices made with gallium arsenide.
Perkembagan in materials science have enabled the production of tools with shorter wavelengths, producing light with varied colors.

Conventional LEDs are made from inorganic mineral that varies, resulting in the following colors:
* Aluminum gallium arsenide (AlGaAs) - red and infrared
* Gallium aluminum phosphide - green
* Gallium arsenide / phosphide (GaAsP) - red, orange-red, orange, and yellow
* Gallium nitride (GaN) - green, pure green (or emerald green), and blue
* Gallium phosphide (GaP) - red, yellow, and green
* Zinc selenide (ZnSe) - blue
* Indium gallium nitride (InGaN) - turquoise and blue
Aluminum gallium indium phosphide * - orange-red, orange, yellow, and green
* Silicon carbide (SiC) - blue
* Diamond (C) - ultraviolet
* Silicon (Si) - blue (under development)
* Sapphire (Al2O3) - blue
READ MORE - Light emission

SCR stands for Silicon Control Rectifier

SCR stands for Silicon Control Rectifier.

SCR Silicon Control acronym stands for Silicon Control Rectifier.SCR Rectifier.SCR acronym stands for Silicon Control Rectifier.SCR Silicon Control Rectifier.

* As a series of switches (switch control)
* As a series controller (remote control)
There are three major groups for these semiconductors are equally able to function as a switch (switching) at a voltage 120 volts to 240 volts.
The third group is itself SCR, DIAC and TRIAC.

DIAC is one type of diode SCR, but it has two terminals (electrodes) alone, in contrast with the "brother" who has three terminals, TRIAC.
DIAC on electronic schematic symbols

In the diagram shows there are five layers in the DIA, has two terminals of the terminal 1 (T1) and terminal 2 (T2).

TRIAC has a construction similar to DIAC, TRIAC contained only the control terminal (gate terminal).
As for the other terminal is called a main terminal and main terminal 2 (abbreviated MT1 and MT2).
As with the DIAC, TRIAC can flow through the alternating current, unlike SCR drain only direct current (from anode to cathode terminal terminal).

TRIAC symbol in the scheme of electronics, has three legs, two of which MT1 terminal (T1) and MT2 (T2) and the other terminal Gate (G)

The triac is equivalent to two parallel connected SCR.
This means that the switch TRIAC can be both directly.
TRIAC classified according to the ability of contacting. TRIAC does not have a very high power capability for this type of SCR.

There are two types of TRIAC, Low-Current and Medium-Current.
Low-Current TRIAC may contact up to a strong current of 1 ampere and has a maximum voltage of up to several hundred volts.
Medium-Current TRIAC can be contacted through strong currents have a maximum of 40 amperes and voltages up to 1,000 volts.

READ MORE - SCR stands for Silicon Control Rectifier

A Zener diode

A diode is usually regarded as the tool that supply power to one direction, but the Zener diodes are such that current can flow in the opposite direction if the applied voltage overshoot "voltage is broken" (breakdown voltage) or "Zener voltage".

Usual diode will not allow electric current to flow in the opposite if the reverse-biased (reverse-biased) below the breakdown voltage.
If the breakdown voltage exceeds the limit, regular diodes will be damaged because of excess electrical current that causes heat.
However, this process is reversible if done within limits.

In the case of rationing-forward (in the direction of the arrow), this diode will provide a voltage drop (voltage drop) of about 0.6 volts for a normal silicon diode.
The voltage drop depends on the type of diode used.

A Zener diode has properties similar to ordinary diode, except that the tool is deliberately made with a much reduced tengangan damaged, called Zener voltage.

A Zener diode has a pn junction which has a heavy doping, which allows electrons to penetrate (tunnel) from the valence band p-type material into the conduction band n-type material.

A zener diode is reverse-biased will exhibit a controlled breakdown and will pass an electric current to keep the voltage drop in order to remain on the zener voltage.

For example, a 3.2 Volt zener diode will show a voltage drop at 3.2 Volts if given the supply and forth.
However, because the current is not unlimited, so the zener diode is typically used to generate a reference voltage, or to stabilize the voltage for small flow applications.

Breakdown voltage can be controlled accurately in the doping process.
Tolerance of 0.05% could be achieved although the most usual tolerance is 5% and 10%.
This effect was discovered by an American physicist Clarence Melvin Zener.

Other mechanisms that produce the same effect is the avalanche effect, as in avalanche photodiodes.
Both types of diodes are actually formed through the same process and the effects actually occur in both types of these diodes.
In silicon diodes up to 5.6 volts, the zener effect is the main effect and this effect showed a negative temperature coefficient.
Above 5.6 volts, the avalanche effect becomes the main effect and also showed a positive temperature coefficient characteristics.

In the 5.6 volt zener diode, both effects occur together, and second temperature coefficients cancel each other.
Thus, diodes 5.6 volt the top choice in the temperature-sensitive applications.
The techniques of modern manufacturing has made it possible to create diodes which have a much lower voltage of 5.6 volts with a very small temperature coefficient.
But with the advent of high-voltage users, the temperature coefficient also appears with the speedy way. A diode for 75 Volt has a coefficient that is 10 times as much heat coefficient of a diode 12 Volt.

All the diodes on top, no matter whatever tengangan damage, usually sold called Zener diodes.


Zener diodes are usually used extensively in electronic circuits.
Its main function is to stabilize the voltage.
At the time are connected in parallel with a source voltage swings are mounted so that the dole and forth, a zener diode will act like a short circuit (short circuit) when the voltage reaches the diode voltage was faulty.
The result, the voltage will be limited up to a figure that has been known previously.

A zener diode is also used like this as a shunt voltage regulator (shunt connection is parallel, and voltage regulator circuit as a class that provides a fixed voltage source.
READ MORE - A Zener diode

Laser diode

Laser diode is a type of laser in which the active medium of a semiconductor pn junction similar to that found on light-emitting diodes.
Diode lasers are also sometimes abbreviated as LD or ILD.

The new laser diode is found at the end of this century by scientists at Harvard University. The working principle of this diode is the same as any other diode through the circuit of the electronic circuit, which consists of type p and n. In both types is often produced two voltages, namely:
1. forward biased, current is generated in line with the value of 0.707 for the distribution of V peak, the wave form above (+).
2. backforward biased, this is turning the voltage that can damage an electronic component.
READ MORE - Laser diode

Photo diode

Photo diode is a type of diode which functions to detect light.
In contrast with ordinary diodes, electronic components will transform light into electrical current.
Light that can be detected by the photo diode is ranging from infrared light, visible light, ultra-violet to X-rays.
Photo diode applications ranging from vehicles on public roads counter automatically, the camera's light meter and some equipment in the medical field.

Tool similar to the photo diode is a photo transistor (Phototransistor).
This photo transistor is basically a type of bipolar transistor using the contact (junction) base-collector to receive light.

This component has a better sensitivity when compared with Photo Diode.
This is caused by electrons generated by photons of light at this junction is injected at the base and reinforced at the collector.
However, the response time of the photo-transistors in general will be slower than on-Photo Diode.
READ MORE - Photo diode

Blue LED

The first blue LEDs that can achieve commercial information using gallium nitride substrates which was invented by Shuji Nakamura in 1993 during a career at Nichia Corporation in Japan.
LED was then popular in the late 90's.

Blue LED can be combined into the red and green LEDs that have been there before to create white light.

With white LED light is now the majority are made by coating a substrate of gallium nitride (GaN) with yellow phosphorus.
Because the color yellow stimulates the red and green color receivers in the human eye, the combination of yellow and blue phosphors of the substrate will give the impression of a white color for the human eye.

White LEDs can also be made by coating the phosphor blue, red and green in the substrate near ultraviolet is more or less similar to the way fluorescent lamps work.

Current methods for creating white light from LEDs is to not use phosphorus at all but uses a zinc selenide substrate which can emit blue light from the active area and the yellow light from the substrate itself.

Jumat, 16 September 2011

signal crossing

compressor to react fast or slowly to an audio signal crossing the Threshold and also how long the compressor keeps working. A loud acoustic guitar being plucked is a good example. With a fast Attack time the musicians playing will be compressed almost instantly. What if you want to hear that definite click of the plectrum plucking the strings? You set a slower Attack time which allows that plucking noise through before the compressor cuts in to reduce the overall volume. Its like shutting the digital barn door after the horse has bolted. Okay, now you want the compressor to turn itself off again in time to hear the next plectrum pluck. So you want a fast Release time to get that compressor out of the way. Otherwise with a slow Release time the compressor will still be on and effecting the following picking.

Different situations call for other approaches. A fast Attack time will help remove plosives, such as microphone popping. If you get your Attack and Release settings wrong it can create a pumping effect as the compressor struggles against the signal.
READ MORE - signal crossing

Kamis, 15 September 2011

GPS front end RF

Built-in GPS front end RF and base band processing module
GPS Antenna Provided
Local Alphanumeric or Graphics display to display Latitude/Longitude/Altitude and Direction
The above parameters can be transmitted through a RS232 output port
This RS232 output is fed to a local wireless transmitter at 433.0 MHz frequency
The range of coverage is 8-10Kms can be expandable to 15Km.
FSK modulation.
Yagi antenna with 8-10dBm Gain for Transmission.
Log scale fidelity : ±2 dB (without attn.) 500 MHz
input attenuator : 0 to 40 dB (4X10 dB steps)
Max.input level :+10 dBm, ±25V DC(odB attn.) +20 dBm (40 dB attn.)
Tracking generator
Output frequency : 0.15 MHz to 1050 MHz
Output attenuator : 0 to 40 dB (4X10 dB steps)
Output impedance : 50 (BNC)
Output level range : -50 dBm to + 1dBm (in 10 dB steps and var)
READ MORE - GPS front end RF

digital communication

We have in store for our clients a quality range of communication trainers, digital communication trainer and analog comminucation trainer etc that has gained appreciation for easy usage and optimum utility. Our range includes analog communication trainers, antenna trainers, mobile trainers and transmission line trainers. These trainers are ideal for conducting varied experiments in the field of telecommunications, electronics and electrical labs.
READ MORE - digital communication


We are amongst the renowned manufacturers and exporters of trainer kits that are available in various models. Our range comprises instrumentation trainers kits, consumer electronic trainers and bio medical trainers. These find application in telecommunication industry, public utilities and medical sector.

We are engaged in offering quality range of instrumentation trainers kit that has gained appreciation for reliable operations. These include ITK-01 LVDT trainer kit, ITK-02 pressure measurement kit, ITK-10 angular displacement kit and ITK 11 thermistor, AD 590 kit.

We offer Basic Science/ Physics Trainers that are generally used in the experiments of science and physics in educational institutes and universities. It is checked on various parameters such as performance, accuracy in readings and durability. The trainers find application in government agencies, academic institutions and research centers.

Digital Interface

XGGCOMMS Icom Digital Interface
Description: This interface offers full CAT control of your Icom Transceiver via your PC's RS-232 port and the Radio's 3.5mm CAT (CI-V) Jack . Additionally, the interface connects your PC sound card line in/out jacks to the radio's 8 pin Din accessory socket for full transmit and receive audio interfacing allowing you to operate modes such as PSK-31, WEFAX, SSTV, PACTOR, Packet, AFSK CW and many more.

This interface is compatible with:
IC-275, IC-375, IC-575, IC-707, IC-725, IC-726, IC-728,
IC-729, IC-735, IC-736, IC-737, IC-738, IC-746,
IC-746Pro, IC-756, IC-756Pro2, IC-756Pro3, IC-761,
IC-765, IC-775, IC-775DSP, IC-7400, IC-7700, IC-7800,
IC-781, IC-820, IC-821, IC-910, IC-970.
READ MORE - Digital Interface


Modular design and flexibly for CPLD
Signal generation unit:
Programmable frequency generator
Standard frequency: 1 — 10MHz
Logic input switch:
8 x 1 logic input original press point with light
8 x 2 logic input Dip switch
4 impulse press button generator
3 x 4 array keyboard
Output unit:
Logic status monitor with total 102 sets LED indicator
8 x 8 dual color point array LCD display
LCD 16 x 2 monitor
6 digits 7 nodes monitor
3 x 4 LED and 1 set buzzer output
Linear unit:
2 sets 8bit D/A converter
1 set 8bit A/D converter
MPU unit:
08051 and CPLD match circuit test
Power source: 220-240V AC, 50Hz, 1Phase
Standard accessories with printed operation manual