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Index 67
Wind Speed & Direction Meter with a Clever Touch （3）
Published:2011/7/26 2:31:00 Author:Amy
G.Samblancat Building it Figure 4 shows the component overlay. The copper track layout may be found on the PCB Layout pages towards the back of this issue. The board consists of a main section and a sensor section. The elongated shape of the board allows it to be mounted in a 32-mm PVC tube, just under the sensor part. Note that presets P1-P4 are accessible from t... (View)
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Wind Speed & Direction Meter with a Clever Touch （2）
Published:2011/7/26 2:04:00 Author:Amy
G.Samblancat Block diagram No remarkable things are seen in the block diagram in Figure 2. The starting point is the pair of Hall sensors arranged at an angle of 90 degrees. Two amplifiers, one for each sensor, condition the sensor signals for use by an ADC and then on to the processor. The ‘limiter’ block pr... (View)
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The XC9215/16/17 Series Synchronous-Rectification Type Step-Down DC-DC Converters
Published:2011/7/26 1:57:00 Author:Phyllis
The XC9215/16/17 series of synchronous-rectification type step-down DC-DC converters, which are in USB-6B (2.0×1.8×0.88mm) package, are an ideal choice for noise sensitive RF applications. These highly integrated DC-DC converters can realize a stable power supply with 400 mA output current with a built-in 0.5-_ P-channel driver transistor and 0.6-_ N-channel switching transistor and an externally connec... (View)
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Simple l2V to 230V Power Inverter--A mobile power outlet （3）
Published:2011/7/26 1:21:00 Author:Li xiao na
Design by G. Gerards More design thoughts The transformer for the project should be a toroidal type with a primary of 230 V and two 12-V secondary windings. Readers in countries with 110 V, 117 V or 127 V mains voltage are, of course, advised to use a matching 200-watt transformer. If you are lucky to have an old toroidal transformer lying around in a drawer or a junk box, it should... (View)
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Simple l2V to 230V Power Inverter--A mobile power outlet （2）
Published:2011/7/26 1:06:00 Author:Li xiao na
Design by G. Gerards Pulsewidth modulation The central part in the circuit is an SG3526 low-cost switch-mode regulator, which is supplied by a number of manufacturers under the component identifier xx3526, where xx is a manufacturer-specific letter combination. The 3526 supports all known switch-mode PSU topologies. Its complete datasheets may be obtained free of charge from wwvj.un... (View)
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Wave catcher （4）
Published:2011/7/26 0:54:00 Author:Phyllis
By Burkhard Kainka Fixed-frequency An alternative to a circuit with adjustable tuning is to use a fixed-frequency filter. In the medium-wave band, there is often only one usable reception frequency. Although the relative bandwidth of the input circuit is relatively large, good selectivity is possible thanks to the low frequency. A circuit such as that shown in Figure 6(View)
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Wave catcher （3）
Published:2011/7/26 0:39:00 Author:Phyllis
By Burkhard Kainka Tuneable The standard approach to building a preselector is to use a tuneable resonant circuit (Figure 3). The coil can be wound as an air-core coil, which means without using an actual core. The wire diameter is not all that important for such air-core coils. For small coils, you can use enamelled copper wire with a diameter of 0.3 to 0.7 mm: som... (View)
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Simple l2V to 230V Power Inverter--A mobile power outlet （1）
Published:2011/7/26 0:38:00 Author:Li xiao na
Design by G. Gerards The absence of a mains power outlet is often keenly felt on camping sites, with car repairs in the middle of nowhere and with picnic or party events in the countryside. In some cases, mains power can only be brought to a remote site by running a very long cable — which either dangerous, impossible or not available. Whatever the occasion, planned or unexpected, it is great to ha... (View)
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Wave catcher （2）
Published:2011/7/25 22:53:00 Author:Phyllis
By Burkhard Kainka A longish wire Strong short-wave transmitters can be received using an aerial system’ (rod aerial or piece of wire) with a length of less than a meter. For long-distance reception, it is naturally much better to use a ’longish’ wire aerial, which preferably should be strung up outdoors - as widely separated from other objects as possible, as h... (View)
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DIY RF Inductors--The ABCs of inductors （7）
Published:2011/7/25 22:50:00 Author:Li xiao na
By B. Kainka Measurements If you do not have a suitable signal generator or dip meter, the only way to measure the resonant frequency of a resonant circuit is to use an oscilloscope. The frequency can be measured by exciting the circuit so it oscillates freely (Figure 8). This requires a steep-edge... (View)
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Wave catcher （1）
Published:2011/7/25 22:46:00 Author:Phyllis
By Burkhard Kainka Aerials and preselectors for AM and DRM For initial experimenting and radio listening with a DIY short-wave or DRM receiver, a simple rod aerial or piece of wire is sufficient. But it’s only natural to want something better. This article gives you the right tips for better reception. In the UHF band, radio waves propagate essentially in a line-of-sight ... (View)
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DIY RF Inductors--The ABCs of inductors （6）
Published:2011/7/25 22:30:00 Author:Li xiao na
By B. Kainka Damping, Q and bandwidth If you know the value of the damping resistance for a resonant circuit, it’s easy to calculate the circuit’s Q factor, and thus its bandwidth. This following example shows how a specific problem can be solved using the LCFR program. Suppose you want to build an aerial filter for the medium-wave frequency of 1296 kHz (BBC, AM and DRM) usi... (View)
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Pandora＇s Sound & Music Box
Published:2011/7/25 22:07:00 Author:Phyllis
By Ken Bromham Recycle an old CD-ROM drive for (triggered) playback This project was originally conceived for model making applications as a cheap way to provide high quality audio playback in response to a trigger signal (typically from a pushbutton or PIR detector), but we’re pretty sure Elektor readers can find many other uses. The standard low cost soluti... (View)
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Wind Speed & Direction Meter with A Clever Touch （1）
Published:2011/7/25 3:04:00 Author:Amy
By G.Samblancat This ingeniously designed circuit may be just the ticket for those interested in weather observations, in particular, wind speed and direction. The clever bit about the instrument is that both wind speed and wind direction are measured with a single sensor: a rotational speed meter with three blades, one fitted with a small vane. One advantage of the specific d... (View)
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DIY RF Inductors--The ABCs of inductors （5）
Published:2011/7/25 2:52:00 Author:Li xiao na
By B. Kainka Some practical examples Suppose you want to wind a 330-/JH inductor for a medium-wave detector radio on a cardboard roll with a diameter of 42 mm. Further suppose that the wire diameter is 0.5 mm, so 100 turns will yield a coil length of 50 mm. Now you can simply try several different values, which ultimately yields a result of approximately 80 turns. For tuning the med... (View)
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Project C+ （2）
Published:2011/7/25 2:51:00 Author:Phyllis
The medium The choice of cable is vital in order to match the pulse profile to the characteristics of the transmission medium and thereby achieve the observed pulse acceleration. After much trial and error in the Elektor Electronics laboratory we concluded that a length of twisted-pair 100 Mbit/s Ethernet cable (CAT5) operated in the sub-hertz frequency range gave the most consistent re... (View)
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DIY RF Inductors--The ABCs of inductors （4）
Published:2011/7/25 2:48:00 Author:Li xiao na
By B. Kainka Inductor calculations using software A small Visual Basic (VB) program called LCFR has been written to make calculations for inductors and resonant circuits. The source and executable code for this program can be obtained free of charge from the Elektor Electronics website. The number is 030398-11, see this month’s Free Download... (View)
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MMC specification version 4.0 is launched
Published:2011/7/25 2:44:00 Author:Amy
MultiMediaCard Association (MMCA) recently introduced version 4.0 of the MultiMediaCard. Its specification features wider bus width, dual voltage operation and the highest transfer speeds. MMCA is a standards organization that promotes the worldwide adoption of MultiMedioCards (MMCs). The new feature-rich version 4.0 specification can be a major expansion of the MultiMediaCard ... (View)
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Project C+ （1）
Published:2011/7/25 2:37:00 Author:Phyllis
Data comms beyond light speed Research papers by their nature are difficult for the average layman to understand. Here in the Elektor Electronics laboratory between the odd cup of coffee we spend much time studying scientific reports. A recent paper by a Japanese research group caught our eye because we were able to replicate the effects described using a very simple circuit and the resu... (View)
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DIY RF Inductors--The ABCs of inductors （3）
Published:2011/7/25 2:34:00 Author:Li xiao na
By B. Kainka Resonant circuits Although resonant circuits are the most important application for inductors, resonant frequency and damping are also significant when inductors are used for other purposes, For one thing, it’s important to recognize undesired resonances, and for another thing, it’s very easy to determine the value of an unknown inductor by using frequency measurement... (View)
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