Friday, June 10, 2011

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0 comments 5:37 PM Posted by Malla Reddy

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Posted: 10 Jun 2011 09:13 AM PDT

An op-amp is usually used as a comparator in cases where its speed and accuracy are not critical. As illustrated in the earlier post (OP-AMP COMPARATOR), the switching speed of the op-amp comparator can be improved and noise can also be eliminated. The offset problems can also be reduced by adding a voltage compensating network and a offset reducing resistor. Since the op-amp is originally designed to act as an amplifier, its output will not act linearly with logic families like TTL. A TTL requires input voltages which range between (0-5) volts. Thus, to keep the op-amp's output voltage swing between these ranges, other components like zener diodes are added onto the circuit. Such circuits with specified output swing are called voltage limiters. Some of the most commonly used voltage limiter circuits are shown below. In the figure shown below, there are two zener diodes that are connected in the feedback path of the op-amp circuit. This design helps in keeping the voltage limit between the positive and negative values of the output voltage, V0. As shown in the waveform, as the voltage Vin increases from 0 to positive voltage, the value of V0 increases in the opposite direction (negative)....

Thursday, June 9, 2011

Hello engineers, Check out our updates

0 comments 9:26 PM Posted by Malla Reddy

Hello engineers, Check out our updates

GEOG-AN-MOD 2011, CTP 2011, RS 2011, call for participation

Posted: 09 Jun 2011 05:37 AM PDT

CALL FOR PARTICIPATION Sixth International Workshop on "Geographical Analysis, Urban Modeling, Spatial Statistics" GEOG-AN-MOD 2011 "Cities, Technologies and Planning" (CTP 2011) Remote sensing Data Analysis, modeling, interpretation and Applications: from a global view to a local analysis (RS 2011) in conjunction with The 2011...

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0 comments 6:02 PM Posted by Malla Reddy

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Voltage Level Detector Circuit

Posted: 09 Jun 2011 04:22 AM PDT

This circuit is designed and submitted by Mr. Rakesh Bute. We are really thankful for his contribution. The circuit as explained by Rakesh: The design came from the interest of finding a new technique of analog to digital conversion. The two types of ADC (Analog to Digital Converter) that inspired me in the development of this circuit are Flash Type ADC and Successive Approximation Type ADC. The Flash Type ADC is the fastest ADC available in the market (highest sampling rate 120 Msps) but it uses a huge number of OP-AMPS. On the other hand Successive Approximation Type ADC uses fewer components but its speed is dependent upon the clock frequency provided to it. I was looking for a technique that can give a trade-off between this two, the result of which is this circuit. Construction The working of this circuit is similar to that of decimal fraction to binary fraction conversion. For this purpose, the circuit amplifies a signal and compares it to a reference voltage. The circuit can be divided into a number of stages. Number of stages can be increased or decreased according to need. Each stage contains two OP-AMPs(TL084). One of them (OP-AMP at the left...

Wednesday, June 8, 2011

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0 comments 5:43 PM Posted by Malla Reddy

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Sample and hold circuit

Posted: 08 Jun 2011 02:24 AM PDT

Sample and hold circuit using opamp. As the name indicates , a sample and hold circuit is a circuit which samples an input signal and holds onto its last sampled value until the input is sampled again. Sample and hold circuits are commonly used in analogue to digital converts, communication circuits, PWM circuits etc. The circuit shown below is of a sample and hold circuit based on uA 741 opamp , n-channel E MOSFET BS170 and few passive components. Description. As the name indicates , a sample and hold circuit is a circuit which samples an input signal and holds onto its last sampled value until the input is sampled again. Sample and hold circuits are commonly used in analogue to digital converts, communication circuits, PWM circuits etc. The circuit shown below is of a sample and hold circuit based on uA 741 opamp , n-channel E MOSFET BS170 and few passive components. In the circuit MOSFET BS170 (Q1) works as a switch while opamp uA741 is wired as a voltage follower. The signal to be sampled (Vin) is applied to the drain of MOSFET while the sample and hold control voltage (Vs) is applied to the source of the...

Tuesday, June 7, 2011

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0 comments 5:53 PM Posted by Malla Reddy

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Moneta – The Future of Computer Storage

Posted: 06 Jun 2011 10:43 PM PDT

Here comes a device that uses "phase-change" memory solid state device that provides a way better performance than the conventional hard discs and other solid state drives (SSD) used today. The device also known as Moneta was developed in Jacobs School of Engineering, UC San Diego. Due to its success, the developers have decided to [...]

Monday, June 6, 2011

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0 comments 5:49 PM Posted by Malla Reddy

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Thin Film Solar Cell

Posted: 06 Jun 2011 04:01 AM PDT

Thin film solar cells are the new generation solar cells that contain multiple thin film layers of photo voltaic materials. The thin film solar cells (TFSC) are also known as Thin Film Photo Voltaic cell (TFPV). The thicknesses of thin film layers are very less as (few nano meters) compared to traditional P-N junction solar [...]

Friday, June 3, 2011

Final Year Projects | IEEE Projects | Application Projects

0 comments 11:08 AM Posted by Malla Reddy

Final Year Projects | IEEE Projects | Application Projects

Privacy-Preserving Updates to Anonymous and Confidential Databases

Posted: 02 Jun 2011 11:50 PM PDT

Privacy-Preserving Updates to Anonymous and Confidential Databases

Suppose Alice owns a k-anonymous database and needs to determine whether her database, when inserted with a tuple owned by Bob, is still k-anonymous. Also, suppose that access to the database is strictly controlled, because for example data are used for certain experiments that need to be maintained confidential. Clearly, allowing Alice to directly read the contents of the tuple breaks the privacy of Bob (e.g., a patient's medical record); on the other hand, the confidentiality of the database managed by Alice is violated once Bob has access to the contents of the database. Thus, the problem is to check whether the database inserted with the tuple is still k-anonymous, without letting Alice and Bob know the contents of the tuple and the database respectively. In this paper, we propose two protocols solving this problem on suppression-based and generalization-based k-anonymous and confidential databases. The protocols rely on well-known cryptographic assumptions, and we provide theoretical analyses to proof their soundness and experimental results to illustrate their efficiency.