Project Solutions

SEALED LEAD-ACID BATTERIES （4）

Published:2011/8/8 21:17:00 Author:Phyllis

In practice Most battery manufacturers recommend charging using a constant voltage and current limiting, with temperature compensation. A simple charging circuit that satisfies these recommendations is shown in Figure 7. An LM317 is used as the voltage regulator with a current limit of 1.5 A. To ensure that the charge voltage is maintained at the level set by PI, the voltag...   (View)

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Rail Router: model train routing with a PC （3）

Published:2011/8/8 21:15:00 Author:Li xiao na

By Ray King Design a track layout... Click on the ’Change Layout Design’ button and the design screen will appear. Click on any square in the layout area, and then click on the required symbol to be put in this square. Continue adding symbols until your layout is complete. Make sure all sidings as well as roads in and out of the layout end with an ’end’ symbol. When done, click ...   (View)

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SEALED LEAD-ACID BATTERIES （3）

Published:2011/8/8 21:04:00 Author:Phyllis

Battery life The life of the battery depends to a great extent on the depth of discharge, expressed as a percentage of the nominal capacity. Figure 5 gives an idea of the effect of cyclic operation on battery life. To maximise the number of useful cycles it is best to choose a battery with a larger capacity so that the depth of discharge is reduced. (View)

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Rail Router: model train routing with a PC （2）

Published:2011/8/8 20:45:00 Author:Li xiao na

By Ray King ... and a dual-purpose circuit board As already suggested by the circuit diagram, the circuit board designed for the Rail Router system can act as a master or a slave, depending on how it is populated. The two different component stuffing plans are given in Figures 3 a (Master) and 3b...   (View)

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RF Control Interface: Parallel interface for remote appliance switching

Published:2011/8/8 4:56:00 Author:Amy

Karl Kockeis There are a number of ’home automation’ systems available that use a hand-held RF control unit to switch household electrical appliances remotely. This article describes some simple interface hardware to link the control unit to your computer’s parallel port and allow automatic control from your PC. The vast majority of printers man­ufactured today connect to the US...   (View)

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One-component Metal Detector 2

Published:2011/8/8 4:13:00 Author:Amy

Rev. Thomas Scarborough Even if you have made something yourself you often want it to have a professional look. Also, if you know space constraints well before starting out on a project, it is perfectly possible to achieve nice looking results. Size of a finished project often equates to ’as small as possible’ so in many cases it is sufficient to make sure a circuit board takes up ...   (View)

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One-component Metal Detector 1

Published:2011/8/8 3:44:00 Author:Amy

Rev. Thomas Scarborough The principle behind a metal detector is really quite simple. The proof: this article, which demonstrates that a detector may be built in a jiffy from just one active component and easi­ly accessible auxiliary items. The design shown here is quite sensitive: depending on tuning, me...   (View)

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10 Gigabit/s Ethernet over twisted-pair copper

Published:2011/8/8 3:26:00 Author:Phyllis

By Phil Turtle If we look back over history, there is an observable cycle out of which has grown the dominance of Ethernet — and which causes the ever-present desire of network managers to ’future proof. Moore’s law states that computing power doubles every 18 months. Although it does not apply directly to active equipment and cabling, it is a significant (View)

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USB Memory Stick: an ideal memory device 2

Published:2011/8/8 2:30:00 Author:Amy

By Harry Baggen Changing the drive letter The block diagram gives a fair impression of the memory chip complexity — a lot of intelli­gence lurks inside the memory to make sure all processes run properly. One of the main points to note with any Flash memory is reli­ability. Flash memory cells do not have eternal life an the odd cell may malfunction dur­ing oper...   (View)

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USB Memory Stick: an ideal memory device 1

Published:2011/8/8 2:17:00 Author:Amy

By Harry Baggen In no time at all, the USB Flash Drive or Memory Stick has become one of the most popular memory devices: small, robust, large capacity, no battery. Now that Elektor Electronics are offering a 128-MB USB Memory Stick as a welcome gift to new subscribers, it’s high time your favorite electronics maga...   (View)

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Rail Router: model train routing with a PC （1）

Published:2011/8/8 2:17:00 Author:Li xiao na

By Ray King Smooth Operator elsewhere in this issue employs model control servos to drive the turnouts on a model railway. One of its advantages is that it can be activated over a single wire making it ideal for computer control described...here! Rail router is a hardware/software combination capable of controlling up to 127 turnouts. The Rail Router hardware...   (View)

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SEALED LEAD-ACID BATTERIES （2）

Published:2011/8/8 1:45:00 Author:Phyllis

Charging In principle sealed lead-acid batteries can be charged at a constant voltage. The maximum charge voltage that can be used depends on the temperature, and it is important that this voltage is not exceeded during charging. Figure 2 shows the relationship between temperature and voltage for two different charging regimes. The higher value is used for normal (cycli...   (View)

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Four in a Row: Play against each other or against the micro! 4

Published:2011/8/8 1:19:00 Author:Amy

By Steve Teal Software The software for the microcontroller is written in assembler and developed using AVR Studio from Atmel. This is freely available from the manufac­turer’s website. Apart from the source code (found in the file ’inaline.asm’), you will also need an include file (2313def.inc), whi...   (View)

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Digital Motors: intelligent drive for servos

Published:2011/8/8 1:17:00 Author:Li xiao na

By Giel Dols Analogue servos are really ingenious bits of hardware. But there’s an even better alternative: the digital servo! Based on the operation of the ’normal’ servo we tell you what’s so much better about the latest digital ones. A servo is a com...   (View)

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SEALED LEAD-ACID BATTERIES （1）

Published:2011/8/8 1:12:00 Author:Phyllis

SLAs still going strong Lead-acid batteries still form an essential part of the on-board power systems in cars, motorcycles, boats and caravans. In its new form, featuring a fixed electrolyte and a sealed enclosure, this veteran battery technology (invented in 1850) is now more versatile than ever. Sealed batteries with a fixed electrolyte have been in production for more than forty...   (View)

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Personal Sound to Light Unit: small but sophisticated （2）

Published:2011/8/8 1:04:00 Author:Li xiao na

By Burkhard Kainka Filter The output signal supplied by the second opamp drives the LED controls by way of simple filters. Each LED driver stage consists of a transistor (T2, T3 and T4). To prevent the transistor bases from being charged with negative levels, anti-parallel diodes (D3, D5, D7) are used on each base terminal. Each transistor is only actuated on the positive half cycle...   (View)

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Vehicle Battery Jogger-keep your battery fresh and young （4）

Published:2011/8/8 0:50:00 Author:Phyllis

By Karel Walraven FETs We have listed several options for FET T1, but the choice here is not critical. It’s also unnecessary to make any changes to the circuit if you use it at 6 V. Still, in this case the preferred type for Tl is the IRF540. That’s because this type of FET works with a lower gate voltage t...   (View)

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Personal Sound to Light Unit: small but sophisticated （1）

Published:2011/8/8 0:48:00 Author:Li xiao na

By Burkhard Kainka Disco nights are great fun from time to time but you don’t want to overdo it in regard of the sound volumes you’re exposed to for a couple of hours. Arguably there’s no less pleasure in enjoying dance music in the privacy of your home, study or student bigs. However, the true disco feeling is not obtained without a matching sound to light unit, so here’s a really smal...   (View)

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Vehicle Battery Jogger-keep your battery fresh and young （3）

Published:2011/8/7 22:56:00 Author:Phyllis

By Karel Walraven Safety Most people don’t realise that despite the modest voltage, working with vehicle batteries can be quite hazardous. This is because such batteries can deliver especially high currents. That means you have to be especially careful with metal objects in the vicinity of a charged battery. A dangerous short circuit can be caused not only by a simple screwdriver or...   (View)

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Precision Function Generator: MAX038 goes SMD （2）

Published:2011/8/7 22:50:00 Author:Li xiao na

By Klaus-Jiirgen Thiesler MLC capacitors Solid, leaded, capacitors in the microfarads range are every expensive, inaccurate and bulky components and it is not surprising to see they are rarely used these days. SMD multilayer ceramic chip capacitors (MLCCs) are much more accurate, tiny and cheap mainly because they are manufactured by the millions for use in mobile phones. Mind y...   (View)

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