Project Solutions

5 volts from the Mains

Published:2011/8/11 1:11:00 Author:Amy

Paul Goossens Sometimes we would like to hide certain equipment to prevent cluttering up our liv­ing room or any interior in general. A number of devices lend themselves to be built into a wall adapter. Think of a remote-control extender, for example. All these devices need a power supply and we would prefer to use the mains so that no external connections are required for the ...   (View)

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BTX

Published:2011/8/10 22:36:00 Author:Amy

Karel Walraven What did you say BTX was again? Well, it’s just the successor of ATX! ATX is the collective term for the electrical and mechanical characteristics of the present generation of motherboards in your PC. There is now a new standard in its place, BTX (Balanced Technology extended Form Factor), with the mai...   (View)

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Cuk Converter （4）

Published:2011/8/10 22:08:00 Author:Li xiao na

By Georg Gerads Construction and alignment A printed circuit board for a DC voltage converter in this power range requires a carefully designed layout (Figure 6), which usually has to be double-sided due to the necessary ground-plane area. The measurement amplifiers, control circuitry and power circuitry are clearly separated from each other, and ’sensitive’...   (View)

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NOISE SUPPRESSION FILTERS - For ClariTy and other final amps （4）

Published:2011/8/10 21:53:00 Author:Phyllis

By Ton Giesberts Be sure to leave the windings leads long enough to allow them to be properly fitted to the circuit board. This will require a bit of ’cut and try’. The inductor is held reasonably firmly on the board by its four leads, but we recommend using a small sheet of plastic and plastic screw to secure it ...   (View)

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NOISE SUPPRESSION FILTERS - For ClariTy and other final amps （3）

Published:2011/8/10 21:47:00 Author:Phyllis

By Ton Giesberts The filter also contains two robust varistors that provide additional protection against sporadic mains disturbances (transients), although they don’t protect against common-mode transients. Rl and R2 ensure that the capacitors are quickly discharged if no mains voltage is present (and ...   (View)

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Cuk Converter （3）

Published:2011/8/10 21:44:00 Author:Li xiao na

By Georg Gerads Control loops For monitoring the currents and voltages in the power section and driving the switching transistors, we use a type 3526 IC. which is available from several manufacturers (including TI and ST). Although- this is a special-purpose IC. it is a well-proven industry standard and thus fairly ’.veil known. Detailed information for this IC is avail¬able...   (View)

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Car Central-Locking System

Published:2011/8/10 21:41:00 Author:Amy

By Christian Vossen For a few pounds you can buy a kit from any automotive accessory shop that will allow your car to be fitted with a central-locking door system. Such a kit essentially comprises a number of motors. There is also a control unit that enables the whole system to function. Here we show an example of such a unit. There are 5-wire motors and 2-wire motors. The 5-wire ...   (View)

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NOISE SUPPRESSION FILTERS - For ClariTy and other final amps （2）

Published:2011/8/10 21:32:00 Author:Phyllis

By Ton Giesberts The inductor uses a very small toroidal core with dimensions of 10 x 4 mm. It has two windings, each just a bit more than a single turn. In practice, this proves to be more than adequate (for our application). Two short (but sufficiently long) lengths of 0.5-mm diameter enamelled copper ...   (View)

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Cuk Converter (2)

Published:2011/8/10 21:26:00 Author:Li xiao na

By Georg Gerads Inductor Unlike most comparable high-power switched-mode regulators, the design of the inductor is not critical with the Cuk Converter, since it conducts a continuous current instead of being switched. The Epcos type E42/21/20 core, which is made from N27 core material, is quite suitable, readily available and a real bargain at less than 7 pounds (including mount...   (View)

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NOISE SUPPRESSION FILTERS - For ClariTy and other final amps （1）

Published:2011/8/10 21:21:00 Author:Phyllis

By Ton Giesberts In the three-part article for the ClariTy 2×300-W final amplifier, the various input and output filters were not described. In this article we remedy that situation. The circuits described here can also give excellent results when used with other designs. Extremely high currents at...   (View)

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Cuk Converter (1)

Published:2011/8/10 20:55:00 Author:Li xiao na

By Georg Gerads The operating principle of the Cuk Converter avoids the need for particular exotic components. That means we can right away take the plunge with a heavy-duty dc converter, which is ideal for use with fluctuating energy sources such as solar systems. The Cuk Converter1 topology yields a theoretically infinite variety of currents and voltages. Consequently, all r...   (View)

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Discrete Robot

Published:2011/8/10 20:50:00 Author:Amy

Gerhard Nocker This simple robot, which responds to light and avoids obstacles, can be built without using a microcontroller, pro­grammer or PC. The only ’special’ com­ponent in the circuit is a window dis­criminator (a fancy version of a window comparator). Resistors R1 and R2 in combina...   (View)

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THERMOELEMENTS （2）

Published:2011/8/10 20:24:00 Author:Phyllis

By Thomas Johann Seebeck Processing the values In a previous publication from our archive, ’Fast, Precise Thermometer’ (Eleklor Electronics January 1992), we already proposed a thermoelement application. In that circuit, the comparison point compensation was handled by discrete components. Today, the semiconductor industry supplies complete, dedicated converters in a chip. An exampl...   (View)

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THERMOELEMENTS （1）

Published:2011/8/10 3:22:00 Author:Phyllis

By Thomas Johann Seebeck Easy processing with the MAX6675 Design engineers like to use thermoelements when it comes to probing around in really wide temperature ranges. Modern integrated circuits are available that act as sensor interfaces to a microcontroller. The operation of thermoelements is b...   (View)

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AUTOMATIC PRESELECTOR for our DRM receiver

Published:2011/8/10 2:10:00 Author:Phyllis

By Burkhard Kainka A PC-controlled receiver is very convenient, especially for DRM, since it makes it easy to locate your favorite stations. However, this advantage is lost if you have a manual preselector and must tune the antenna by hand: an automatic preselector is what you need! With a PLL-controlled receiver things are very simple. The PLL tuning voltage can be used simultaneou...   (View)

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CuK TOPOLOGY: Little-known but still highly interesting （2）

Published:2011/8/10 2:01:00 Author:Li xiao na

By Georg Gerods Operation To understand how the converter works, you need to have a basic understanding of how inductors behave. When a dc voltage is applied to an inductor, the current increases linearly from an initial value of zero with a slope di/dt = U/L. When the voltage is switched off, the current decreases, again ...   (View)

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GOODBYE ＇16, WELCOME PIC18F Part 2: ROM （program memory） and long lookup tables （2）

Published:2011/8/10 1:46:00 Author:Phyllis

By Ron Coates The ability to address this amount of space hinges on table pointers. There are three of these, TBLPTRU (Table Pointer Upper) only 5 bits of which are available, TBLPTRH (Table Pointer High) and TBLPTRL (Table Pointer Low). Together these are used to form a 21 -bit long address which can access up to two megabytes. In practice, with the (View)

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CuK TOPOLOGY: Little-known but still highly interesting （1）

Published:2011/8/10 1:41:00 Author:Li xiao na

By Georg Gerods The topology of the Cuk converter was first published in the 1980s, but it is rarely encountered in practice even today. However, this circuit concept offers enticing advantages for many power supply applications. The Cuk converter is a capacitively coupled converter that generates an adjustable output voltage and current by periodically charging a capacitor. As the circuit (in i...   (View)

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GOODBYE ＇16, WELCOME PIC18F Part 2: ROM （program memory） and long lookup tables （1）

Published:2011/8/10 1:37:00 Author:Phyllis

By Ron Coates The 18Fxx2 series of processors have either 16 k or 32 k of Flash ROM. However, each program instruction takes at least one word (i.e., two bytes) so in terms of the number of lines of program code you could wri...   (View)

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Back to the Future: Home electronics from the （recent） past 5

Published:2011/8/10 1:32:00 Author:Amy

Dimmer with a MOSFET Ton Giesberts This circuit shows that dimmers intended for use at mains voltage do not always have to contain a triac. Here, a MOSFET (BUZ41A, 500 V/4.5A) in a diode bridge is used to control the voltage across an incandescent bulb with pulse-width modulation (PWM). A useful PWM controller can be found elsewhere in this issue. The power supply voltage for driv...   (View)

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