Project Solutions

Slave Flash for Digital Cameras: Don’t throw away your old flashlight （2）

Published:2011/8/4 21:55:00 Author:Amy

Udo Burret Construction Building this circuit is unlikely to cause problem if you use the printed circuit board artwork shown in Figure 2. Do pay attention to the orientation of the diodes, ICs and Tl. The phototransistor’s case is not unlike that of an LED. The (View)

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Clarity 2x300W Class-T Amplifier-Part 2: building amplifier board （4）

Published:2011/8/4 21:49:00 Author:Phyllis

By Ton Giesberts Coil winding Winding the output inductors is not difficult, but you must pay careful attention to the winding method. With the selected wire diameter of 1.5 mm (16 SWG), the 29 turns will not fit on the selected core in a single layer. To keep the internal capacitance as small as possible...   (View)

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Clarity 2x300W Class-T Amplifier-Part 2: building amplifier board （3）

Published:2011/8/4 21:38:00 Author:Phyllis

By Ton Giesberts Power supply and ground The main supply voltage is connected to the circuit board using flat (car-type) terminals. This allows very large currents to flow and makes it easy to connect the board to the power supply. Special electrolytic capacitors are fitted across the power supply terminals to decouple the worst RF current spikes. We have done our best to implement ...   (View)

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Clarity 2x300W Class-T Amplifier-Part 2: building amplifier board （2）

Published:2011/8/4 21:24:00 Author:Phyllis

By Ton Giesberts Suppressing inductive spikes Due to the physical dimensions of the components, parasitic self-inductance and overshoots will always be present. The consequences of this, particularly the inductive spikes (backemf) from the inductors in the output filters, can be partially suppressed...   (View)

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Clarity 2x300W Class-T Amplifier-Part 2: building amplifier board （1）

Published:2011/8/4 21:18:00 Author:Phyllis

By Ton Giesberts A pulse-width-modulated output stage with hi-fi characteristics is something rather special. We already described various aspects of this design in the June 2004 issue. Following that introduction, in this installment we continue with a description of how to build this powerhouse. The pulse-width modulated (View)

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Slave Flash for Digital Cameras: Don’t throw away your old flashlight （1）

Published:2011/8/4 2:41:00 Author:Amy

Udo Burret Although most digital cameras have a built-in flash, a connection for an external flashlight is rarely seen. Still, on some occasions it’s useful to have just a tad more light and that’s why we propose a simple add-on. As many of you will be able to avow, the light capacity of the flash facility ...   (View)

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ClariTy 2x300W Class-T Amplifier Part 3: power supply assembly and alignment （5）

Published:2011/8/4 2:13:00 Author:Amy

Ton Giesberts Alignment The only alignment that is required is to adjust the dc offsets of the outputs, which can be done after the amplifier is assembled but should preferably be done during testing before final assem­bly. Naturally, the dc offset voltages must be set to zero. The offsets must be adjusted (using PI and P2 on the amplifier board) with the amplifier switched on a...   (View)

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Smooth Ope: for Model Railway Turnouts and Semaphores （2）

Published:2011/8/4 2:09:00 Author:Li xiao na

By Ray King Printed circuit board The printed circuit board (PCB) for the turnouts control has been spaciously laid out. What’s more, it contains standard size components only. The component overlay is given in Figure 2. Easy to use PCB terminal blocks with 5 mm pin spacing are used for the connectors, except Kl which is a 3-pin pinheader for use with ready-made ser...   (View)

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Smooth Ope: for Model Railway Turnouts and Semaphores （1）

Published:2011/8/4 1:58:00 Author:Li xiao na

By Ray King In many model railway layouts, electromagnets instantly snatch turnouts and semaphores from one position to another with an associated ’clunk’ noise. Armed with a PIC micro and a small servo, the circuit described in this article provides much slower, smoother, quieter and hence more realistic operation of these mechanical devices. There are a large number of model railw...   (View)

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ClariTy 2x300W Class-T Amplifier Part 3: power supply assembly and alignment （4）

Published:2011/8/4 1:42:00 Author:Amy

Ton Giesberts Assembly For our prototype, we chose the ’not so quick-and-dirty’ method and fabri­cated our own enclosure from a sheet of aluminium. This results in an uncon­ventional design, whose shape and proportions are determined by the dimensions of the heat sink, toroidal transformer, power-supply capacitors and power supply board (Figure 2). The heat sink forms the fr...   (View)

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Design Your Own IC--Part 2: CPLDs in practice （6）

Published:2011/8/4 1:29:00 Author:Li xiao na

By Paul Goossens Counter If you analyse the Verilog code, you will see that the value of register temp is incremented on each clock pulse. As soon as the register reaches the value 4,000,000, register D is incremented by the value ’1’, temp becomes ’0’ and output SLOW becomes ’1’. If register temp has not yet reached the value 4,000,000, SLOW receives the value ’0’. With a 4.000-MHz...   (View)

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ClariTy 2x300W Class-T Amplifier Part 3: power supply assembly and alignment （3）

Published:2011/8/4 1:16:00 Author:Amy

Ton Giesberts Main power supply The compactness of the amplifier is off­set by the sheer mass of the power supply. Of course, we could have also developed a switch-mode power sup­ply, but it would have to be a supply that could deliver a good 40 A at a bit less than +/- 60 V. That would be a challe...   (View)

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Design Your Own IC--Part 2: CPLDs in practice （5）

Published:2011/8/4 1:14:00 Author:Li xiao na

By Paul Goossens Latch The final block in the schematic is a latch. A latch is also a frequently used type of component in digital designs. The operation of a latch is actually quite simple. As long as the clock input is T, the latch’s output must be the same as its input. If the input state changes, the out...   (View)

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ClariTy 2x300W Class-T Amplifier Part 3: power supply assembly and alignment （2）

Published:2011/8/4 1:02:00 Author:Amy

Ton Giesberts Auxiliary voltage and switch-on delay The 10-V supply for the output stage is also powered by a separate trans­former (TR2). After rectification and fil­tering, the voltage is stabilised using a standard positive 10-V regulator. If a 10-V regulator is difficult or impossible to obtain, a 9-V type can also be used. Two different types of transformer are shown on...   (View)

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Design Your Own IC--Part 2: CPLDs in practice （4）

Published:2011/8/4 0:45:00 Author:Li xiao na

By Paul Goossens Always @ Up to line 46, there’s nothing new to be seen. But in line 46 you can see something added to the keyword always: an @ character followed by a comparison. This code segment can also be seen in Listing 2. The @ sign indicates that the procedural statements belonging to this always statement are only allowed to be evaluated (but not ’executed’...   (View)

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Design Your Own IC--Part 2: CPLDs in practice （3）

Published:2011/8/3 22:40:00 Author:Li xiao na

By Paul Goossens Programming As already mentioned in Part 1 of this article, to program the CPLD you will need the JTAG programmer described in the September 2002 issue of Elektor Electronics. Of course, an original Altera ByteBlaster is also OK. We assume that your programmer is connected to the printer port of the PC and the JTAG connector is attached to connector K2 of the experi...   (View)

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ClariTy 2x300W Class-T Amplifier Part 3: power supply assembly and alignment （1）

Published:2011/8/3 22:20:00 Author:Amy

Ton Giesberts As already mentioned in the previous parts of this article, this final amp needs more than just a heavy-duty symmetrical power supply. In this final part, we examine the main power supply, the other power supplies, final assembly and alignment. The analogue input portion of the TA3020 operates from a stabilised 5-V supply voltage. A stabilised 10-V auxil-iary voltage i...   (View)

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Air Quality Sensors: New CO2 Sensors for Air Quality Monitoring （2）

Published:2011/8/3 22:01:00 Author:Amy

Christian Voit---Unitronic AG The TGS4160 gas sensor The TGS4160 consists of a CO2-sensitive solid electrolyte cell with an internal thermistor for temperature compensa­tion. Figure 2 shows the construction of the sensor and a cross-section through the sensor element. A NASICON disc with a diameter of 4 mm and a thickness of 0.7 mm is printed with gold electrode...   (View)

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USB EMBEDDED HOST CONTROLLER （2）

Published:2011/8/3 21:37:00 Author:Phyllis

By Mark Schultz SCSI Many mass storage devices use SCSI commands for communication between the host and the device. We will be using three SCSI commands to perform our file operations. The commands are Inquiry, Read Capacity and Read(lO). The format of the three SCSI commands to be used in this design is shown in Table 2. (View)

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USB EMBEDDED HOST CONTROLLER （1）

Published:2011/8/3 21:32:00 Author:Phyllis

for removable mass storage devices By Mark Schultz Till now USB has been available only on personal computers, leaving large, untapped potential in the area of embedded systems. New embedded host controllers from Cypress herald a new era. An embedded system is defined as hardware and firmwa...   (View)

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