DRAM cell operation

What is DRAM?

   Dynamic random-access memory (DRAM) is a type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit. The capacitor can be either charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1. Since capacitors leak charge, the information eventually fades unless the capacitor charge is refreshed periodically. Because of this refresh requirement, it is a dynamic memory as opposed to SRAM and other static memory.

Operation :

  •Write:

–1. Drive bit line

–2. Select row

•Read:

–1. Precharge bit line to Vdd/2

–2. Select row

–3. Cell and bit line share charges

»Minute voltage changes on the bit line

–4. Sense (fancy sense amp)

»Can detect changes of ~1 million electrons

–5. Write: restore the value

•Refresh

–1. Just do a dummy read to every cell.

Hardwork can never ever fails...
Best Luck...

Microcontroller and its application

What is microcontroller?

A highly integrated chip that contains all the components comprising a controller. Typically this includes a CPU, RAM, some form of ROM, I/O ports, and timers. Unlike a general-purpose computer, which also includes all of these components, a microcontroller is designed for a very specific task -- to control a particular system. As a result, the parts can be simplified and reduced, which cuts down on production costs.

Application:BPS

BPS Stands for 'Bata Positioning System'. This system provides real-time information about the current position of each team's current runner in the Batavierenrace.

Last years system used a GSM module, a GPS receiver, a microcontroller and a lot of programming. They were all connected trough a lot of wires and soldering iron. Together with some batteries it was our BPS-box. This box was sending a SMS-message every minute with the latest position of the runner.


How does it works?

Using a GPS device, we will monitor the location of a team. This location data will be parsed by a microcontroller, which then creates an SMS containing all the necessary info (including Date, Time, Speed and course). Using a GSM, which is bundled with the GPS device, this SMS will be sent to a remote server. There, the SMS messages will interpreted, entering the information they carry into a database. With this information, the exact location of each team can be projected onto a map (together with additional info like speed, and estimated time of arrival).

Hardwork can never ever fails....
Best luck....

Sensor and it types

Defn:
        A sensor (also called detector) is a converter that measures a physical quantity and converts it into a signal which can be read by an observer or by an (today mostly electronic) instrument.
        It operates based on the vibration produced by viscometer.


Types:

Defect detector, used on railroads to detect axle and signal problems in passing trains

Engine coolant temperature sensor, or ECT sensor, used to measure the engine temperature

Hall effect sensor, used to time the speed of wheels and shafts

MAP sensor, Manifold Absolute Pressure, used in regulating fuel metering.

Mass flow sensor, or mass airflow (MAF) sensor, used to tell the ECU the mass of air entering the engine

Oxygen sensor, used to monitor the amount of oxygen in the exhaust

Parking sensors, used to alert the driver of unseen obstacles during parking manoeuvres

Radar gun, used to detect the speed of other objects

Speedometer, used measure the instantaneous speed of a land vehicle

Speed sensor, used to detect the speed of an object

Throttle position sensor, used to monitor the position of the throttle in an internal combustion engine

Tire-pressure monitoring sensor, used to monitor the air pressure inside the tires

Torque sensor, or torque transducer or torquemeter measures torque (twisting force) on a rotating system.

Transmission fluid temperature sensor, used to measure the temperature of the transmission fluid

Turbine speed sensor (TSS), or input speed sensor (ISS), used to measure the rotational speed of the input shaft or torque converter

Variable reluctance sensor, used to measure position and speed of moving metal components

Vehicle speed sensor (VSS), used to measure the speed of the vehicle

Water sensor or water-in-fuel sensor, used to indicate the presence of water in fuel

Wheel speed sensor, used for reading the speed of a vehicle's wheel rotation

Hardwork can never ever fails...

Best luck..