To go from 45° to 90° requires two HMC1501 sensors or a single HMC1512 dual sensor part. By using two bridges with 45° displacement from each other, the two linear slopes can be used additively. Figure 8 shows a typical configuration. From Figure 8, as the shaft rotates around, magnetic flux from a magnet placed at the end of the shaft exits the north pole and returns to the south pole. With a HMC1512 placed on the shaft axis, just above the magnet, the flux passing through the sensor bridges will retain the orientation of the magnet. From this rotation, the output of the two bridges will create sine and cosine waveforms as shown in Figure 9.

Because the sine (sensor bridge A) and cosine (sensor bridge B) will match after the offset error
voltages are subtracted, the ratio of bridge A to bridge B creates a tangent 2O function and the amplitude A values cancel. Thus the angle theta is described as:

However because there are some trigonometric nuances with the arctangent function when gets close to _45° and beyond, these special cases apply:

Because most trigonometric functions are performed as memory maps in microcontroller integrated circuits, these kinds of special case conditions are easily dealt with. The resultant angle theta is the relative position of the magnetic field with respect to the sensor. It should be noted that if rotation is permitted beyond _90°, the theta calculation will replicate again with postive and negative 90° readings jumping at the end points. Further performance to 360° or _180° can be mapped into a microcontroller by using this circuit plus a Hall Effect sensor to determine which side of the shaft is being positionally measured via magnetic polarity detection. Figure 10 shows the basic circuit interface for the HMC1512.

HMC1501 / HMC1512
Linear / Angular / Rotary
Displacement Sensors
High resolution, low power MR sensor capable of measuring the angle
direction of a magnetic field from a magnet with <0.07>

HMC1501 Datasheet pdf

Technorati Tags: WIDER POSITION SENSING CIRCUIT

Bidirectional Hall Effect Based Linear Current Sensor with
Voltage Isolation and 20 A Dynamic Range


ACS706ELC-20A
The Allegro ACS706 family of current sensors provides economical
And precise solutions for current sensing in industrial, automotive,
commercial, and communications systems. The device package allows
for easy implementation by the customer. Typical applications include
motor control, load detection and management, switched-mode power
supplies, and overcurrent fault protection.
Current Input Range Min -20 A Max 20 A
Output Voltage versus Current Input (Vcc = 5V)

Features
• Small footprint, low-profile SOIC8 package
• 1.5 mΩ internal conductor resistance
• Excellent replacement for sense resistors
• 1600 VRMS minimum isolation voltage between pins 1-4 and 5-8
• 4.5 to 5.5 V, single supply operation
• 50 kHz bandwidth
• 100 mV/A output sensitivity and 20 A dynamic range
• Output voltage proportional to ac and dc currents
• Factory-trimmed for accuracy
• Extremely stable output offset voltage
• Near-zero magnetic hysteresis
• Ratiometric output from supply voltage

ACS706ELC-20A Datasheet pdf


Technorati Tags: Bidirectional Current Sensor

The AD202 are general purpose, two-port,transformer-coupled isolation amplifiers
In applications where the output ofthermocouples must be isolated, a low drift input amplifier can be used with an AD204,as shown in Picture.

A three-pole active filter is included in the design toget normal-mode rejection of frequencies above a few Hz and to provide enhanced common-mode rejection at 60 Hz.
If offset adjustment is needed, it is best done at the trim pins of the OP07 itself; gain adjustment can be done at the feedback resistor. Note that the isolated supply current is large enough to Mandate the use of 1 mF supply bypass capacitors.

This circuit from AD202 Application

Technorati Tags: Isolated Thermocouple Transducer Circuit

AS5145
12-Bit Programmable Magnetic Rotary Encoder
The AS5145 is a contact less magnetic rotary encoder for accurate angular measurement over a full turn of 360 degrees. It is a system-on-chip, combining integrated Hall elements,analog front end and digital signal processing in a single device. To measure the angle, only a simple two-pole magnet, rotating over the center of the chip, is required. The magnet may be placed above or below the IC.The absolute angle measurement provides instant indication of the magnet’s angular position with a resolution of 0.0879º = 4096 positions per revolution. This digital data is available as a serial bit stream and as a PWM signal.An internal voltage regulator allows the AS5145 to
operate at either 3.3V or 5V supplies.

Typical magnet (6x3mm) and magnetic field distribution

Daisy Chain Mode
The Daisy Chain mode allows connection of several AS5145’s in series, while still keeping just one digital input for data transfer (see “Data IN” in Figure 9). This mode is accomplished by connecting the data output (DO; pin 9) to the data input (PDIO; pin 8) of the subsequent device. The serial data of all connected devices is read from the DO pin of the first device in the chain. The length of the serial bit stream increases with every connected device, it is n * (18+1) bits: n= number of devices. e.g. 38 bit for two devices, 57 bit for three devices, etcetc.

AS5145 Datasheet

Technorati Tags: Magnetic Rotary Encoder to Microcontroller Circuit

This circuit used convert signal from Rotary encoder (A,B) to two pulse signal
- Y for CCW direction
- X for CW (clockwise) direction
Two pulse signal is easy for microcontroller programing
The circuit used two D-type flip-flop(74HC74D) for the judgement.

Signal input and signal out put

Technorati Tags: Rotary encoder converter circuit

We can use series RC circuit and voltage comparator to generate
a time delay. Two resistors R2 and R3 are used as a voltage divider
which applies about two-thirds of the Vcc voltage to the positive
comparator input The delay time after the Vin change form low to
high will be around one time constant

Time constant = R1C1 = 100K * 10uF = 1 seconds.

The delay time can be adjust by adjusting R1 or change C1

Technorati Tags: Simple delay time circuit

We can use inverting Schmitt trigger circuit for this application
Inverting Schmitt trigger
the circuit can be view as an inverting –type threshold detector whose
threshold is controlled by the out put since the output has two stable
state, this threshold has two possible values,namly

Vth = R1*Voh/(R1+R2)
Vtl = R1*Vol/(R1+R2)

The hysteresis width is defined as
Hw = Vth – Vtl = R1*( Voh – Vol )/( R1 + R2 )
Behaviour of circuit show in below picture.

Sample waveforms

Technorati Tags: On-Off Control With Hysteresis Circuit

We can make simple Large Fan-In AND Gate circuit by one Voltage Comparators from circuit below

Vout = A and B and C and D and ….

This circuit is application of LM139
LM139
Low Power Low Offset Voltage Quad Comparators
The LM139 series consists of four independent precision
voltage comparators with an offset voltage specification as
low as 2 mV max for all four comparators. These were
designed specifically to operate from a single power supply
over a wide range of voltages.

All pins of any unused comparators should be tied to the
negative supply.

The output of the LM139 series is the uncommitted collector
of a grounded-emitter NPN output transistor. Many collectors
can be tied together to provide an output OR’ing function.

Vo = A or B or C


Technorati Tags: Simple Large Fan In AND Gate circuit

We can use a voltage reference turn into a Constant current source
circuit and use pnp-transistors for current-boosting

By op amp action ,the voltage across R is away Vref , give
Ie = Vref / R

Ie = Ib + Ic = (Ic/B) + Ic

Ic = [B/(B+1)] *Ie

Io = Ic = [B/(B+1)] * Vref / R about Vref / R
VL = Io*RL
Where maximum voltage of Vl(max) <>

We can adjust output current by adjust current setting resistance R


Technorati Tags: Constant current source circuit

A half-wave rectifier is a circuit that passes only the positive or only the negative
Portion of a wave ,while blocking out the other portion
Rectifiers are impremented using diodes. The nonzero forward-voltage drop of
A pactical diode may cause intolerable errors in low-level signal

Proceeding of half-wave precision rectifiers circuit we separate are two case
Case 1 Vi > 0 negative input of op amp is higher positive input ,the op amp
Output = 0 ,I1 will flow through R1 and D1 ,hence Vo = 0
Circuit behavior
Vo = 0 for Vi > 0
Vo = -(R2/R1)Vi for Vi <>
Example waveform

Technorati Tags: rectifiers circuit, Half wave precision rectifiers circuit

The AD620, along with another op-amp and two resistors, makes a precision current source circuit.

The op-amp buffers the reference terminal to maintain good CMR. The output voltage, VX, of the AD620 appears across R1, which converts it to a current. This current, less only the input bias current of the op amp, then flows out to the load.
where
Vx = [(Vin+) – (Vin-)] * G
IL = Vx / R1
Circuit operates on 1.8 mA, ±3 V

Gain(G) is resistor-programmed by Rg
Rg = 49.4K ohm / (G-1)

Technorati Tags: Precision Voltage, Current Converter Circuit, Precision Voltage to Current Converter Circuit

            Almost all the equipment and tooling a little or a lot relies on electronic technology. Therefore, almost all aspects of human life is influenced by the use of semiconductor materials in electronic products. The use of semiconductors in various electronic equipment will increase with increasingly sophisticated electronic products. The most widely used semiconductor predicted by the computer industry (57%), communication equipment (17%), household electronic equipment (15%) and the remaining approximately 11% for other purposes, such as military equipment, automotive and industrial machinery. Research reactors are often equipped with various facilities, one of which is a facility for producing doped semiconductor materials. Making new materials with different structures from the original material can be done with the technique of neutron irradiation. Because the absorption of neutrons, then the stability of atomic nuclei become disturbed and raw materials will be transformed into other isotopes with different physical properties of elements from the original. This technique turned out to be used to produce semiconductor materials, especially the changing characteristics of silicon (Si) into pure silicon tercangkok with phosphorus (P) with a certain level, thus serves as an excellent semiconductor material. With neutron transmutation doping facility (neutron doping facility) in a nuclear reactor can be used to perform neutron irradiation on Si semiconductor sample that generally occur in nature with atomic number 30. Because the irradiation process is then very small portion of the nucleus 30Si will absorb neutrons and become radioactive nuclei 31Si, 31Si decays subsequently became 31p. With this technique can be obtained by neutron irradiation of semiconductor materials Si tercangkok P through nuclear reaction as follows:

30Si + 1n Æ [31Si]* —> 31P + b-

             In this modern century, the semiconductor is a very important component and is a major part of almost all electronic circuits. Semiconductor Si with P dopant is widely used for the manufacture of transistors, thyristors for high voltage and CCD video camera. Developed a new generation of electronic computers using the increasingly tiny microprocessors that are physically performed with a smaller size, but with a working speed which is much higher. Reniknya more electronic components are also demanding more and more pure semiconductor materials it uses. Neutron irradiation technology was able to meet these demands, even the best methods currently available for the manufacture of semiconductor materials with very high purity level.

             The development of electronics technology has brought order to switch from micro to nano, which means that electronic components will be made in the size of a thousand times smaller than the previous generation of microelectronics. Manufacturing process of semiconductor materials with neutron irradiation technique can be performed with excellent results, so that support towards the realization of nano-electronics technologies in the future. P dopant levels can be regulated by irradiation techniques appropriate timing. Electronic components such as transistors are usually very sensitive to pollution, eg, Si contamination during manufacturing. With neutron irradiation techniques, the presence of impurities, other impurities that are not desired in the production of components made from semiconductor can be avoided since before the irradiation process.

             Refrigerator Can Create Unique internet. Refrigerator certainly no longer the electronic device that 'wah'. However, what if the fridge is equipped with internet access that allows us to display the image on the screen on the refrigerator door?

             That breakthrough presented by Samsung in the refrigerator makes. South Korean electronics giant is developing an e-Diary Zipel refrigerator with a door that has a touch screen measuring 10 inches (about 25 cm).

             This refrigerator is equipped with Wi Fi software that allows users to surf in the virtual world, read internet news, weather forecasts, or view pictures and data.

             Not only that, as quoted from the AFP, this unique fridge can also send and receive pictures from mobile phones.

             Refrigerator e-Diary Zipel dibanderol priced at U.S. $ 2,174 or approximately USD 20 million. Unfortunately, this refrigerator will only be sold to consumers in South Korea. Samsung plans to market the device is not yet widely available.

             The use of irradiation technology is big enough in the process of an industrial chemical. Because it brings high energy, radiation may act as a catalyst to stimulate the chemical changes suatuÆÒhan, one of which is to change the type of liquid chemicals from organic compounds in the class of monomers into polymers. One of these is the nature of the monomer when receiving radiation exposure can be turned into new materials called polymers, which is a very hard solid material at room temperature. Polymer-making technique with the help of this radiation is called radiation polymerization. In industry, radiation polymerization technology can be used to produce high-quality plastic because of its very strong and resistant to heat.

             In general it can be said that the polymerization is an effort to combine several elements into one cohesive substance. Utilization of the results of irradiation in the polymer industry the most is for the manufacture of electric cable insulation material. Irradiation causes long-chain molecules in polymers holding in certain places that the process known as crosslinking (crosslinking). Radiation energy can stimulate the occurrence of crosslinking between the polymer thus formed three-dimensional network that can change the properties of polymers. These events actually cause cable insulation materials are more resistant to heat and high voltage electricity.

            Cables can never be separated from the mains. In almost every electronic item we can find a cable in it. In general, we know the cable usually consists of one or more metal conductors are wrapped with insulating material. Cables of this type often do we meet both for the transmission or delivery of electric current electric pulses in telecommunications. Electrical cable insulation material is generally made from polyethylene plastic or polyvinyl chloride (PVC). The second is a kind of linear polymers, ie polymers which soften or melt when heated. Insulating material weakness is certainly not desirable for the cable used in the appliance or a particular installation.

          Conductor metals currently used for power transmission cables are still a prisoner-in, thereby causing electric current dialirkannya partly converted into heat which is known as Joule heating. The higher the temperature, the higher the resistance-in, so that more electrical energy converted into heat dialirkannya. Because of Joule heating, too, the strong currents flowing in the cable should be limited. That is why, certain electronic goods, computers for example, equipped with a fan to remove heat that occurs in the circuit-circuit.

          PVC plastic is made of polymer material can maintain the density of the irradiation at much higher temperatures than ordinary PVC (the result of chemical processes). With this irradiation technology, cable insulation materials become stronger, more elastic, and more resistant to oils and other chemical solutions. This advantage can be achieved without causing changes in electrical properties as well as insulating power.

          Irradiation technology can also modify polyethylene polymer product can be shrunk if the volume is given a heat treatment which is often referred to as heat shrinkable tubes. This product is widely used in the electric industry to insulate electrical connections. Heat shrinkable tubes are also often used in the telecommunications industry for the packing units such as cable telephone cable unit, to be shielded from outside influences, more durable, safe and can be planted in the ground.

          Irradiation technology is very efficient and economical to manufacture polymeric small-diameter cable insulation material that is widely used in electronics industry which requires high accuracy, such as computers and telecommunications aircraft. For some types of electronics products, the use of high quality cable is often a necessary condition, so our product really can be reliable and competitive.

          Very thin surface layer (membrane) on a silver oxide batteries used in digital watches and calculators, as well as the surface of the floppy disks and tape record the video tape, are processed using irradiation technology. Researchers from Japan have succeeded in making polymer membranes of cellulose that is used for microphone or a magnifying system of acoustic sound. This high-quality membranes are being developed for the manufacture of commercial sound systems and high-quality musical instruments. In the field of energy, solid polymer electrolyte (solid polymer electrolyte) can be used to manufacture chemical fotoelektro cells. These polymers are made from polyethylene oxide (PEO) that is coupled with potassium jodida (KJ) and jodium (J2). Research in this field still continues to be developed to obtain a system of solid polymer electrolyte which would later be used as batteries for solar electric generating systems (solar energy).

             There are three types of nuclear reactor viewed from its intended use. First is the reactor used for research purposes is commonly called research reactors (research reactors). Second was reactor designed to produce electricity, commonly called power reactors (power reactor) and used in Nuclear Power Plant (NPP). Third is a reactor designed dual role, namely as a producer of electricity (as a power reactor) and the production of fissionable fuel (breed nuclear fuel), commonly known as breeder reactor (breeder reactors).

             Research reactors have a very big role in the utilization of nuclear techniques in the outer energy. This type of reactor neutron results only use nuclear fission reactions, it is hot out of the nuclear reactions that will be discarded. Because the use of neutrons, the reactor neutron flux experiment was designed to have large enough so that suitable as a means to perform irradiation with neutrons. Neutron flux in order to achieve the optimum, then the reactor core is surrounded by blocks berlillium (Be) and a few lines of Be element as a neutron reflector. In addition, because the heat is not utilized, then the research reactor designed low thermal power, which range from a few hundred kilo Watt (kW) to tens of mega watts (MW).

           Utilization of nuclear techniques outside the energy sector can be done with the involvement of research reactors and research reactors without engaging directly. Which involves the utilization of research reactors generally is by neutron irradiation in the reactor core. The process of neutron irradiation is widely used for research in medicine, physics, chemistry, biology, agriculture, industry, environmental studies, metallurgical materials and so forth. Moderate use of nuclear techniques that do not involve direct research reactors are usually done with memanfaatakan radiation emitted by radioisotopes. With this technique, irradiation can be done outside the reactor core. Radioisotopnya own being produced by the technique of neutron irradiation in the reactor core.

           Gamma irradiation with radioisotopes used extensively in various fields. Irradiation technology has been applied in chemical processes of an industry. Without realizing it is actually a lot of industrial products used in everyday life contain components manufacturing process involving irradiation technology. Of plastic goods for domestic use can be made through the irradiation process. Items such as television sets or cars for example, contains the components and cable wrapping process is strengthened by irradiation.

            Tools Developed Terrorist Mind Reader. Concerns of the international community against terrorist attacks is still missing. To anticipate, the experts had developed a mind reader devices are considered able to anticipate any future attacks.

            Computer experts and psychologists from Northwestern University, United States claimed that they were able to read the mind of the terrorists were caught and they will know the location plan the next assault. The team placed electrodes on the scalp terrorists and examining their brain waves.

            Tests conducted with the involvement of approximately 29 students who provided a number of planned attacks. Students are positioned as a terrorist.
     
              For the first study, students are then questioned about the attack plans, and of course the researchers actually know about these mock terrorist plan. But their purpose in the early stages of this research is to monitor how the student brain wave patterns when answering questions about where and when the attack took place.

              As the initial stage, according to psychology Professor J. Peter Rosenfeld, expressing a sense of guilt in the information occurs in the 'P300 waves'.

            In the next stage, researchers do not know the plan of attack and then the students are asked to not tell the location plan. The researchers found that when given the wrong information P300 wave showed a pattern that is not the same. So the most likely terrorist patterns give the wrong information but when the P300 pattern similar to early stages of testing so it's most likely true.

            "This test is 83 percent accurate in predicting the hidden information, and can show a complex protocol and can identify future terrorist activities," said Rosenfeld.