Project Solutions

RF Detection

Published:2011/8/21 22:01:00 Author:Li xiao na

By David Daamen WiFi detectors are small gadgets that claim to detect wireless access points for computer networks. The effectiveness of these devices is already covered in many Internet articles, but here you will find out exactly how they work. To begin with, we opened the first device we had to hand; see Figure 1 (Kensington ’WiFi Finder’). It was immediately app...   (View)

View full text | Comments | Reading(1003)

Remote Thermometer for the PC: PC data logger with email alerting 2

Published:2011/8/21 22:00:00 Author:Amy

Cyril Jouanjan Sensor connections The sensor used here, the DS1621, already contains practically all the nec­essary components. The IC also con­tains a built-in thermostat, but that functionality is not used in this project. The accuracy of the DS1621 is of the order of 0.5°C without the need for any special calibration. The measuring range spans from -55°C to +125°C and the...   (View)

View full text | Comments | Reading(1284)

Remote Thermometer for the PC: PC data logger with email alerting 1

Published:2011/8/21 21:47:00 Author:Amy

Cyril Jouanjan With the aid of a PC and intelligent temperature sensors it is very easy and quick to assemble a professional temperature data-logger. Using e-mail, up to four temperatures can be monitored from a distance. The sensors are simply connected to the PC parallel port. In this article we describe a system that measures and records tempera* lures. The heart of the system ...   (View)

View full text | Comments | Reading(494)

HIGH-END POWER AMP-High-class watts （6）

Published:2011/8/21 21:46:00 Author:Phyllis

By Ton Giesbets Don’t solder the driver transistors, output transistors or quiescent-current transistor to the circuit board just yet. The leads of these transistors must first bent to the right spacing, so they can rest properly on the heat sink without any mechanical strain after being fitted. That is described in detail under ’Final assembly’. Next comes the (View)

View full text | Comments | Reading(1425)

LED Bedside Lamp: with turn-off delay

Published:2011/8/21 21:36:00 Author:Li xiao na

By Eduard Heger If you are not lucky enough to have access to expensive test gear then lamp circuits using LEDs offer a good chance of success and allow a little bit of electronic experimentation. simple but useful addition to the bedside table. The lamp is activated either by pressing a push button or automatically when the...   (View)

View full text | Comments | Reading(1596)

HIGH-END POWER AMP-High-class watts （5）

Published:2011/8/21 21:29:00 Author:Phyllis

By Ton Giesbets Power supply A separate printed circuit board has been designed for the power supply (Figure 4). It just fits into the enclosure between the transformers. The power supply design is quite conventional, with a standard 80-VA toroidal transformer, rectifier, and electrolytic smoothing (View)

View full text | Comments | Reading(3157)

HIGH-END POWER AMP-High-class watts （4）

Published:2011/8/21 21:11:00 Author:Phyllis

By Ton Giesbets IC1 is a fast dual opamp (type AD827). Here ICla is configured as a difference amplifier that compares the two signals at its inputs. R8 and R9 attenuate the loudspeaker signal by a factor of two (10.5÷2). This means that IClb only has to provide a gain of 3.5 (10.5 ÷ 2 ÷ 1.5). The gain of ICla can be adjusted using PI to compensate for variations in component values. In the...   (View)

View full text | Comments | Reading(499)

HIGH-END POWER AMP-High-class watts （3）

Published:2011/8/21 21:02:00 Author:Phyllis

By Ton Giesbets To protect the loudspeakers against output offset voltage transients that may occur when the mains voltage is switched on, a switch-on delay is provided for the output relay. The delay time is approximately 6-7 seconds. The state of the relay depends on the supply voltage for the final amplifier, rather than the (View)

View full text | Comments | Reading(1330)

Marconi TF1152 RF Wattmeter

Published:2011/8/21 20:46:00 Author:Li xiao na

By Jan Builing In line with this month’s locus on all things Wireless I am coveting a vintage instrument that has given me many years of excellent service and peace of mind at o very small investment indeed. If you like to work with (View)

View full text | Comments | Reading(3032)

Frequency Spectrum from DC to 30 GHz in 4 pages 4

Published:2011/8/21 20:44:00 Author:Amy

Paul Goossens Galileo A number of European countries are collaborating on a project to create a network similar lo GPS. Just like GPS this network makes it possible lo determine your position very accurately. This new sys­tem, christened Galileo, also uses a network of satellites in space. It is anticipated that this system will be even more accurate than the current GPSI. <...   (View)

View full text | Comments | Reading(408)

HIGH-END POWER AMP-High-class watts （2）

Published:2011/8/21 20:43:00 Author:Phyllis

By Ton Giesbets As can clearly be seen, all of the operating points in the amplifier are directly dependent on these two current sources, so we gave particular attention to their design. The reference voltages for the current sources are provided by flat LEDs, which in turn are operated at reasonably constant currents provided by a ...   (View)

View full text | Comments | Reading(470)

HIGH-END POWER AMP-High-class watts （1）

Published:2011/8/21 20:38:00 Author:Phyllis

By Ton Giesbets The High-End Preamp preamplifier published in the April & May 2004 issues naturally calls for a matching final amplifier in an identical housing. Due to the restricted size of the enclosure, the output power of this final amplifier is somewhat on the modest side, but the quality is outstanding...   (View)

View full text | Comments | Reading(6928)

＇Edwin＇ Audio Amplifier （1975）

Published:2011/8/21 20:17:00 Author:Phyllis

By Jan Buiting Blending in beautifully with this month’s focus on all things Audio I’d like to take you back to September 1975 when Eleklor magazine published an audio amplifier named ’Edwin’. 1975 was the first full year the English-language version of Elektor was published. Not surprisingly, the then editors looked at designs that had already proved extremely popular in the German and Dut...   (View)

View full text | Comments | Reading(6055)

Frequency Spectrum from DC to 30 GHz in 4 pages 3

Published:2011/8/19 4:36:00 Author:Amy

Paul Goossens 27 MHz The 27 MHz band, also known as CB {Citizens Band) or 11 meters, lies between 27.60 MHz and 27.99 MHz in the UK, and between 26.96 MHz and 27.41 MHz in the EU. In the UK a license is required (o use CB, although in many other European countries this is no longer the case. Lorry drivers and cabbies are one group of people who are well known for their use of CB to ...   (View)

View full text | Comments | Reading(346)

Frequency Spectrum from DC to 30 GHz in 4 pages 2

Published:2011/8/19 4:32:00 Author:Amy

Paul Goossens Professional communications Apart from radio and television broadcasting, there are many more applications where radio is used for the exchange of information. Just think of the communications in aviation, shipping, the police, etc. These particular groups also hove various parts of the sp...   (View)

View full text | Comments | Reading(325)

Frequency Spectrum from DC to 30 GHz in 4 pages 1

Published:2011/8/19 4:29:00 Author:Amy

Paul Goossens Life without wireless communications is almost unthinkable in the modern world. These days virtually everybody makes use of some type of transmitter or receiver: GSMs, broadcast radio and TV, WLAN, Bluetooth, and so on. And there is still a lot more happening in the radio spectrum. In this article we show what else can be found in ’the ether’. Over the years, organizat...   (View)

View full text | Comments | Reading(386)

Wireless Microphone: Audio in the ISM band 4

Published:2011/8/19 2:15:00 Author:Amy

Ton Giesberts Interface Thanks to these complex modules that include almost all the necessary elec­tronics, what remains is straightfor­ward. Figure 4 shows the two parts of the circuit. In the transmitter we can either connect a microphone or any other desired audio source with a max­imum output level of -15 dBV. In most cases, however, an electrets micro­phone will...   (View)

View full text | Comments | Reading(3649)

Wireless Microphone: Audio in the ISM band 3

Published:2011/8/19 2:07:00 Author:Amy

Ton Giesberts The receiver The block diagram of the WA-RX-01 receiver module shown in Figure 3 is practically the mirror image of the transmitter, using similar components. RF band-pass filter (SAW...   (View)

View full text | Comments | Reading(1269)

Wireless Microphone: Audio in the ISM band 2

Published:2011/8/19 2:01:00 Author:Amy

Ton Giesberts The transmitter Figure 2 shows the functional blocks of the WA-TX-01 transmitter. We will look at each in turn. Input buffer (BUF) This circuit is an input buf...   (View)

View full text | Comments | Reading(1681)

Wireless Microphone: Audio in the ISM band 1

Published:2011/8/19 1:55:00 Author:Amy

Ton Giesberts The WA-TX-01 (transmitter) and WA-RX-01 (receiver) modules represent a novel concept in the wireless transmis­sion of audio signals. Thanks to low power consumption, the technology leads itself to a wide range of audio applications. The transmitter and the receiver include components such as SAW fi...   (View)

View full text | Comments | Reading(2397)

Pages:3/22 1234567891011121314151617181920Under 20