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Spectacular Spectra

Every electronics enthusiast dreams of making a hi-fi deck at least once in his life time. While he dreams, he plans, “the deck set will have excellent sound quality and wattage. It will be equipped with a 10-band graphic equaliser. Each band of the graphic equaliser will be accompanied by a IQ-level spectrum analyser. And when lights in the ten bands of the spectrum analyser will dance with the beats of drum and throbs of cymbals, what a great display will it be! «But when becomes back to reality and faces the great expenses involved, he has to omit a

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Stereo headphone audio amp on AD822AN

The amplifier is designed for use with stereo headphones. This audio amp is economical, can be operated from a single low-voltage power supply and at the same time has good technical characteristics. Total harmonic distortion of output signal span at 300 mV (peak to peak) at a frequency of 1 kHz is 0.079% (-62 dB with noise).

Stereo channels are input via the separating nonpolar capacitors C1 and C2. Voltage divider resistors R1-R2 and R3-R4 at the noninverting input circuits are chosen so that the outputs of op amp present voltage (1.5 V) equal to half the supply. The gain

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Digital Frequency Counter

A digital frequency counter (DFC) is used for building, testing and designing analogue and digital circuits, li can also be used for measuring the frequency of any periodic waveform.

The fundamental operation is shown in the block diagram in Fig. 1.

The cost of a DFC is largely governed by the number of digits in its display and the maximum input frequency it can handle. An inexpensive instrument would typically offer a 4-digit display. This frequency counter* incorporating all the features, is comparatively cheaper.

A DFC normally has several measuring ranges. It is possible to add a few digits to

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Bison LPP — 750 — 115E

Network saber saw can be made straight, oblique and shaped cuts in a variety of materials — wood, chipboard, plastic, metal, foam and others. Power 750 Watt motor would be enough to solve the problems of the traditional circle.

Operation of the instrument is simple. The speed is controlled in the range of from 300 to 2500 strokes per minute. Required range is selected wheel located on top of the housing.

The saw blade at the LPP — 750 — 115E mounted using quick-chuck. The supplied key only need to adjust the desired cutting depth — change the angle

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Automatic Voltage Stabiliser

Conventional voltage stabilisers are used for feeding controlled voltage to refrigerators, TVs, VCRs etc where AC input varies predominently during peak loads. These stabilisers normally use one or two relays and voltage is available in two steps. In first step the output is 240V AC at 240V AC input while in second step the output is 240V AC at 220V or 210V AC input. If input goes below 220/210V AC, the output state varies but to a lesser extent.

The other type of stabilisers available in the market are the manual autocut kind. In such stabilisers the output voltage is

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Adaptive Schmitt trigger tames unruly signals

Sometimes we are faced with the need to extract information from very noisy signals, for example, biomedical measurements. I needed to generate a square wave signal from the respiratory sensor, which differ greatly in amplitude and frequency, and, in addition, with a non-baseline. Presented here adaptive «super-Schmitt» with lots of customizable options perfect job of cleaning input.

Component values ​​shown in scheme selected for input ranges from 50 mV to 1 V peak-to-peak at a frequency of 0.07 Hz to 2 Hz.

U1 and U2 track the positive and negative peaks of the input signal, but, in contrast to

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A Versatile Decibel Meter

A decibel meter is an instrument I to measure levels of input signal(s) in decibel units. The main areas of application of decibel meters are audio level indicators, record level indicators, spectrum analysers and the like.

The circuit shown here provides a resolution of 20 steps. Although the steps are linear, they are calibrated with corresponding decibel value so that it suits lost of the requirements.

The circuit is shown in Fig. 2. It is based on IC LM3914 integrated circuit intended for bar graph generator circuits. The IC has 11 op-amps, out of which one is used for buffering

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Answer Euro march organizers Minsk city executive committee will tomorrow

City officials said they can not collect on October Square and about the structure of the State Library. According to them, it can make a danger to public order, because both places are in close proximity to the subway entrance.Chairman of the organizing committee of Euro march Viktor Ivashkevich disagreed with the accusation authorities about the site near the library, saying, there held frequently held massive official events.In conjunction with this action the applicants said they could change their place of gathering — instead of October Square will be collected about Yanka Kupala, where there is no entrance to the

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Stubb: In Ossetia required international peacekeepers

Minister of Foreign Affairs England David Miliband said on arrival in Brussels, one of the political consequences of the Russian-Georgian conflict has been the actual effect so called "Big Eight" influential states in the format "Big Seven" without Russia. He also stated that all the great need for a common EU energy policy:"I think the need for a common energy policy has increased as a result of the events that we are currently watching."David Miliband accused the Russian authorities in undisguised anger and called on them to provide evidence that Georgia did zlachnstvy war in South Ossetia, specifically because it

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Area input of residential premises in Russia increased by 7% in 2011

The total area input of residential premises for the period from January to December 2011 amounted to more than 60 million square feet. m, almost 7% more than in the corresponding period of 2010.

The population in 2011 due to the gearing was built more than half of the total housing commissioned in January-December of this year.

In 2011, three quarters of commissioned housing in Russia accounted for the Central, Volga, Siberian and Southern Federal Districts. In the context of regions the largest share in 2011 won the Moscow region — more than 10% of the

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