Rabu, 24 Oktober 2012

Germanium diodes

Germanium diodes are a type that has been in use since the early days of radio and although they have been largely superceded by silicon signal diodes and integrated circuits, they may still be found as signal diodes in older radio circuits, where they are used in such applications as radio signal detectors (demodulators) where the voltages involved in demodulating AM radio signals are likely to be small, less than 1Vpp (0.5Vpk). Germanium diodes will conduct at a forward voltage of only about 0.15V, but a silicon diode will not start to conduct until a forward voltage (positive on the anode) of 0.6V is reached.

The demodulator that recovers the audio signal from the amplitude modulated (AM) radio waves can use a germanium diode as a rectifier to remove the unwanted half of the AM signal. It works in a similar way to a rectifier diode in a simple power supply; it passes one half of the incoming radio signal and blocks the other half. The main differences being that the frequency of operation is much higher, also the voltages used in a demodulator are tiny by comparison to a mains (line) power supply.

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Silicon rectifier

Silicon rectifier diodes, are used in many applications from high voltage, high current power supplies, where they rectify the incoming mains (line) voltage and must pass all of the current required by whatever circuit they are supplying; this may be several tens of Amperes or more.

Carrying such currents requires a large junction area so that the forward resistance of the diode is kept as low as possible. Even so the diode is likely to get quite warm. The black resin case helps dissipate the heat.

The resistance to current in the reverse direction (when the diode is "off") must be high, and the insulation offered by the depletion layer between the P and N layers extremely good to avoid the possibility of "reverse breakdown", where the insulation of the diode fails due to the high reverse voltage across the junction.

Silicon diodes are made in many different forms with widely differing parameters. They vary in current carrying ability from milli-amps to tens of amps, some will have reverse breakdown voltages of thousands of volts; others use their junction capacitance to act as tuning devices in radio and TV tuners. Look in suppliers lists to see the many types available.

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Light-Emitting Diode (LED) circuit

Usually, circuit is made with some basic parts such as capacitors and resistors. Those basic parts are then built into some several combination that structure building blocks for other circuits.

Some people who have enough experiences might not find any difficulty in designing electronic circuit. First, you need to know well about the characteristics and behavior of either intermediate or advanced components of electronic circuit. Sometimes, you can find sample circuits that will help you get more information in using the parts. Some parts that usually contain this information are including semiconductors such as diodes, transistors, as well as op-amps.

Second, you should also learn more about some basic circuits used in many kinds of electronic devices. You will also get this information easily from any basic electronics text. For example, you can have more practices in modifying a Light-Emitting Diode (LED) circuit.

Simple Ways To Understand The Filter Capacitors In Electronic Circuits

Executive SummaryBy Jestine Yong

You could see mica capacitors, ceramic capacitors, tantalum capacitors, aluminum electrolytic capacitors, paper capacitors and etc. Electronic Field - Act as filter to remove ripple in power supplies;

- As inter stage signal coupling capacitors- A capacitor will not pass DC, but an AC signal will go through;

- Tuning resonant circuits, oscillator circuits;

In today's article I'm going to talks about capacitor act as filter to remove ripple from power supplies. Usually, the filter includes one or more capacitors. The capacitors are then placed between the DC line and ground. This unwanted noise signal can cause problems in electronic circuit. If all capacitors checked okay I would then move on to another circuit. Why not one filter capacitor is enough for each DC line voltage? The answer is that the big filter capacitors (large value) at the secondary side of power supplies is to smooth the DC and remove unwanted lower frequency noise.

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IC 4511

The IC 4511 is a BCD to 7-segment decoder driver. Its function is to convert the logic states at the outputs of a BCD, or binary coded decimal, counter like the 4510 into signals which will drive a 7-segment display. The display shows the decimal numbers 0-9 and is easily understood.

There are two important types of 7-segment LED display. In a common cathode display, the cathodes of all the LEDs are joined together and the individual segments are illuminated by HIGH voltages. In a common anode display, the anodes of all the LEDs are joined together and the individual segments are illuminated by connecting to a LOW voltage.

The 4511 is designed to drive a common cathode display and won't work with a common anode display. You need to check that you are using the right kind of display before you start building.

The 0.56 in. 7-segment display common cathode available from Rapid works well as part of a prototype board circuit.

When the 4511 is set up correctly, the outputs follow this truth table:

In normal operation, the lamp test and ripple blanking inputs are connected HIGH, and the enable (store) input is connected LOW. The circuit diagram shows the 4511 and a 7-segment common cathode display connected to the outputs of a 4510 BCD counter:

To build this circuit follow the prototype board layout from the 4510 Beastie Zone web page and then add the 4511 with connections to a third prototype board, as shown below: 


simbul elektronic

simbul elektronic The diagram below shows passive components, resistors, capacitors and inductors, and also electrical components such as switches, relays, motors and lamps. Also shown are the symbols for wires that are not joined ( no physical electrical connection ) and wires that are joined ( a physical electrical connection ).

This next diagram depicts active components, the difference between active and passive is that active components require a power source to work, whereas passive components do not. The top symbols represent vacuum tube or thermionic devices. Although at one time, these were being replaced by the smaller transistor and integrated circuits, they are finding their way back into electronics for use in professional audio equipment and some radio receivers 
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Selasa, 23 Oktober 2012

IC TDA1554

This is a simple circuit. Just use a single IC, but the amplifier has 4 channels, 11 channels per watt, which is Philip IC TDA1554 number suitable for listening at home or in any vehicle. Just because the power supply 12-15 volt or will be used to expand any home theater sound system. The first 2-channel amplifier front speakers. And 2 to extend the back surround sound speakers also. This circuit power supply 12 volts to 18 volts Power consumption at 5A. The input 4 input pins 1, 2, 17 and 18 is divided into a horizontal input inverter Ting 2 channels (Pin 1, 17). inverse model and input object 2 channels (pins 2, 6). That we can use that. To output phase to phase or did not return. The output will be the fourth slot on the leg 6, 8, 12, 10, with a C7-C10 serves to increase the low frequency stability better before you go to the speaker. The switch S1 acts on mute by pressing S1 will be closed sound system circuit in Mute, and if open circuit S1 standby ready to work. The C5 and C6 will filter light to smooth out and eliminate interference.

Kamis, 18 Oktober 2012

Resistor color

Electronic components are essential fizikal elements in electronic systems. Each component has a direct impression of the functioning of electronic equipment. The components are connected with each other by using a solder (solder) on board litar printed (PCB) to produce electronic litar tertentu.Contohnya function litar amplifier (amplifier), radio receiver and litar rectifying AC to DC.

The components inside the pakej disepadukan recognized as litar bersepadu. (Integrated Circuit). Party of electronic components is an obstacle (resistor), capacitors, and transistors diod. Each of these components has a different function in guarding and electron currents in electronic litar.

I will explain briefly about each of the components that are commonly used in coaching litar.

1. Jinx (Resistor)

Jinx gives an immediate impression of the electric current and Voltan. Ohm is used to measure the hurdle every obstacle. For the measure we use Ohm meter hurdles.

We may know the value hurdles by looking at the color cod wrapped around the obstacle.

Carta below shows the value for each Resistor color.

To determine the value of the barrier hurdle, color kod read begins with the color first, second and third followed by silver or gold as the value of tolerance.

For example, if we Want to get barrier 250 Ohm. The color red for 2, green for 5 and multiplied by ten namely brown color for all three loops. 250 Ohm = red, green, brown. Silver followed if the value of tolerance of 10% or 5% gold.

Cuba you get to color kod barrier 10 K Ohm.

Jawapannya is - brown, black, orange.

Cuba looking for color barrier that is worth 220 Ohm, 330 Ohm, 470 Ohm, 1 Ohm K and 8.2 K Ohm.

Now you also know why there is a color that wrapped around the obstacles and hurdles value may think.
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Electronic Diesel Control (EDC)

Electronic Diesel Control (EDC) is an electronic engine-
management system for diesel engines. Bosch presented
the first system of this kind in 1986. All control and regulation functions are combined in one electronic engine control
unit to which the injection system and a large number of
sensors are connected.

Bosch Electronic Diesel Control ensures ideal diesel
injection control at all engine operating points. It evalu-
ates in real time sensor data on the temperatures of
coolant, fuel and charge air as well as the momentary
engine speed, the position of the accelerator pedal
and the intake air mass. From these values the EDC
calculates the best possible injection process.

In addition, EDC is the prerequisite for a number of
further systems which increase the comfort of the diesel
engine while reducing emissions and consumption.
These include, among others, the electronic accelerator
pedal, automatic speed control (Tempomat) or regulation
of engine idling speed to a constant value. Above and
beyond this, EDC permits On Board Diagnosis as well
as data exchange with other on-board computers such
as the management system for up-to-date automatic transmissions. This ensures that the engine operates
in the sector most favourable to consumption while also
making jolt-limited, high-dynamic gear changes possible.

Systems and components
Electronic Diesel Control (EDC) Cylinder shutoff
top of page
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Selasa, 16 Oktober 2012

Digital clocks

Building a digital clock is a great project with a rewarding climax. The 6-digit clock described here, besides being a great conversation piece, will make an outstanding piece of furniture for your desk or living room.

Digital clocks, list most accurate instruments, are expensive. However, since the advent of IC's and with advances in the state-of-the-art a digital clock can be a reality. This clock can be build for about $250.00 with six digits as described here. For the more economically minded, a four digit model can be made for considerably less, leaving out IC10 and IC8, V5 and V6. A little scavanging (like we all seem to be masters at), and a well-stocked scrap barrel can also do wonders in saving the bank roll.

 The Nixie tube readouts can be remoted. This gives the builder the utmost in freedom of design. Two of the clocks on the cover are good examples of this technique. The black desk-set clock was originally a desk radio that was redesigned and converted into a six-digit clock. Its electronics are packaged separately and can be unobtrusively secured to the side of a desk. The cramped space dictated the use of rectangular Nixie tubes type B.

The red clock started life as a bed lamp. After a trip to a junk shop it was resurrected and now is a four-digit clock with the electronics mounted behind the bezel. A friend of mine packaged the readout for his clock in a roll-on deodorant can and mounted it on the neck-piece of a broken goose neck lamp. He packaged the electronics in the base. It's a real Buck Rogers masterpiece that fits well into his modern home furnishings. A trip through a second-hand junk store or your local drug store will give you many great ideas for a great new and original clock design.

 The two most important ingredients in my lock, the IC's and readouts, were chosen very carefully. THe IC's are the heart of the clock I was especially careful here. I use SN7490N counters and SN7441N Nixie tube drivers made by Texas Instruments. They have good noise immunity for a 5V IC and can be counted on for reliability and long life. The Burroughs B-5750S Nixie tubes were chosen because they were originally designed for a calculator market as a high pressure tube and they are the best available when one digit must remain on for any length of time. (The 0 in the first digit is on for 9 hours at a time, the 1 is on for 3 hours.)

How it works
Clock operation can be broken down into basic subsystems - the 13 o'clock reset circuit, the basic counting circcuits, the timing circuits and, of course, the power supply.

 The power supply is a simple half-wave rectifier that provides pulse input tot he timing circuits. Also provision is made through transistor Q5 and the 6.3V Zener diode for 5.6 volt Vcc. Also B+ is tapped from the 117 Vac input and converted to +170 Vdc by the voltage booster D9, R16, and C1. Capacitor C12 is installed across the secondary to remove line transients on the input pulse (see Fig. 1).

Timing circuit
 The half-wave 60-Hz input to the timing circuit is shaped to positive square wave pulses by Q4 and associated circuitry (see Fig. 5 and Fig. 3). The resulting 60-Hz square wave is applied at pin 14 of the divide by 10 counter, IC 12. These counters count on the negative going side of the square wave. Output from IC 12, a 6 pps square wave, is applied to pin 14 of IC 13, a divide by 6 counter. IC 13's output is a 1 pps square wave which is applied to pin 14 of IC 11. The counter is wired in a divide by 10 configuration. It resets when 9 is displayed and the square wave goes negative. The counter outputs standard 8421 BCD which is applied to readout driver IC 10. Basically IC 10 is a BDC to decimal decoder driver with output transistors that can handle enough current to directly drive the Nixie tube. It provides the first seconds digit for a 0 through 9 readout. When the 9 is displayed on the first Nixie tube, V6, codes D and A (see logic table) go high as the counter resets to zero and D goes low. IC 9, the divide by six counter, is pulsed. The BCD output of this counter is decoded and displayed on V5, the second significant digit in the clock. This cycle repeats with IC 9 counting once for each 10 counts of IC 11.

 When IC 9 reaches 5, logic codes C and A are high. C (pin 8) is connected to the input pin (14) of IC 7 which is the first digit of the "minutes" section of the clock. IC 7 and its associated decoder driver, IC 6, are wired in the same configuration as the 0-9 indicator in the seconds second (IC 11, IC 10 and V6). Operating IC 7 and IC 6 cause 0-9 minutes to be displayed on V4. When 9 comes up, logic D and A are high and cause an input to be felt at pin 14 of IC 5, the 0-5 portion of the minutes indicator. (Remember, the count occurs as the pulse goes toward the negative in these counters.) The minutes 0-5 is wired exactly the same as the seconds 0-5 section and operates in a similar manner. When 5 is displayed on V3 and logic C and A is high, the C is felt on pin 14 of the divide by 10 counter, IC 3. This counter counts once each time IC 5 resets and is wired similarly to IC 7 and IC 11 with the one important difference described in the next paragraph.

Reset circuit
 The problem in the hours circuit is that V2 must count from 1 o'clock to zero as V1 indicates 1 for 10 o'clock. V2 must then count 1 and 2, then reset to 1 o'clock. This is done by wiring decoder driver IC 2 so it thinks it is displaying a 0 on V2 when it is actually displaying a 1. When it thinks it is displaying a 1, it actually showing a 2 and so on until it displays a 0 which the decoder driver thinks is a 9. After the zero is displayed the counter resets to zero, logic D and A are high causing flip flop IC 1 to change state and turn off Q1 and turn on Q2 which extinguishes the 0 displayed on V1 and lights the 1. (See Fig. 2).

As V2 counts to a 3 (would appear as 13 on hours indicators V1 and V2) logic B goes high which causes pin 2 of IC 2 to go high. Simultaneously current flow through D2 is routed from B to E of Q3 causing pin 2 of IC 1 to go low and reset the flip flop. The result is that 0 lights on V1, pins 2 and 3 in IC 3 are high and IC 3 resets to 1. The count cycle 1-0 begins again for the second half of the 24-hour day.

Construction tips
Assembling this project can be extremely complicated because of the number of ICs and associated components. To simplify procedures a bit I strongly recommend using IC sockets. There are two reasons. First and foremost, if you apply too much heat to an IC lead, chances are you'll zap the IC and when you consider you will be soldering upwards of 180 IC leads your odds are short on a perfect job. Second and of paramount importance from an operational standpoint, is the fact that IC characteristics will vary somewhat and a quick switch of ICs may solve a problem that otherwise might have to be corrected by a value change in the associated circuitry.

Tables are provided for both component to component and point-to-point Vector board wiring. Either method is effective. However, if you are not an experienced builder with many "projects" under your belt I'd suggest using the Vector board chart as it is the simplest and most straightforward.

Follow the steps in the order listed and you will be home free after a few evenings of enjoyable labor.

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Jumat, 12 Oktober 2012

Program cosmonau

Program cosmonaut State leads triumphant first spaceman, Dr Sheikh Muszaphar Shukor in October off the historical record but not a meaningful point he met noktah. I not likely that free than glory are listed by Sheikh Muszaphar, it also followed the triumph of bringing the investigation to Stesen transnational Space. The program is expected to provide a major impact in the field of science and inquiry, especially for the three types of investigations carried it. By aligning Life Science program, Prof Dr. A. Rahman A. Jamal, the design of the project and the investigation is important if only in black and white empire decided to continue the program as offered by the Russians. "Cost me less after the astronauts landed," he told a meeting at the officials in the Hospital Universiti of Malaysia (hukm), recently. However, he is also Director Institute of Molecular Biology tuber Universiti Kebangsaan Malaysia said, tugasannya perceived that the decision has not completed the investigation is not yet known. Tempatan scientists and investigators involved in Universiti Kebangsaan Malaysia (UKM), Universiti Malaya (UM), Universiti Putra Malaysia (UPM) and Universiti Teknologi Mara. The investigation involves kanser cell run by his own, Prof bacteria. Dr. Ramelah Mohamed and protein crystallization by prof. Dr. Raja Noor Zaliha Raja Abd. Rahman of Universiti Putra Malaysia (UPM). He gave an example, the investigation of the cell kanser important to look for new inventions that enable new treatment can be found perceived that the threat of a killer disease into four or 40.000 chan year. He said investigations involve kanser hepatic (liver) is important and necessary field studies. He said, all three investigations are in the process of analysis includes Jepun. He preliminary report or "interim decision" can be issued to put forward to the Ministry of Science, Technology and Innovation (MOSTI). "Overall analysis and decision be known as early as the beginning of this year," he said, adding that free inquiry brought to the ISS was not experiencing any problems or disturbances during Soyuz landing. He hoped that any judgment obtained can later be encouraged to continue the investigation on the ISS royal triumph Malaysia perceived that it got the attention of the world in particular several space agencies. Jepun Space Agency (JAXA) for example, had a meeting with his party in November off to establish cooperation in the future in the field of investigation airspace off. Indeed, he hoped the desire to run an investigation is like it was in 2011 that the mission offered by Russia can be implemented. This said, the bid was opened to allow scientists to expand their investigation into the corresponding space is taken off. Malaysia was offered instead Agency Russian Space Alliance (Roskosmos) to deliver astronauts to the space between the two countries separated in late 2010 or early 2011. Had agree, it will involve many areas of technology including satellite, remote sensing, navigation, telecommunications and scientific studies that may be conducted on a mission to come. Bagiamanapun, fac Minister of Science and Innovation, Datuk Dr. Maximus Ongkili recently explained, the offer since the decision muktamad Agency Russian Space Alliance (Roskosmos) to deliver astronauts to the space separated the two countries will only be known in the entire period two months. Ongkili said, there are any similar decision to accept or otherwise the offer will be known only after an assessment study of the program conducted in the State spaceman off. "It should be made in advance of their study program spaceman State before boarding his deep regard in which he was 70 peratus involve reciprocal agreement with Russia's Sukhoi aircraft purchases," he said. Whatever the decision of the kingdom of the astronaut program so after a second case but the investigation were available and were analyzed it was expected to give a new chapter to the field of R & D in the country. According to Dr. A Rahman, scientists require a period of at least three years to make preparations to run investigations on ISS for them to know for sure the model and its suitability. In the first mission, approximately 50 investigations acceptable than scientists place but after undergoing the process. Investigation is necessary to run the ISS suitability as the equipment and suitable habitat. He gave an example, there is an investigation before it had to be rejected. One more cabaran investigators Tempatan provide perkakasan or hardware is suitable for such investigation and it would open a new history in the field of science in the country in case they prove the ability to produce its own equipment.
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