Wednesday, 25 March 2015
Tuesday, 24 March 2015
Soldering iron temperature controller
R1 15 Kilo-Ohm
P1 250K potentiometer
C1 823K, 250V
D1,D2 1N4004 or 1N4007
D3 Diac, bilateral trigger type
Q1 Triac 500V/25A, BT136
Open Loop & Close Loop Speed control for induction motors.
Open Loop Speed control for induction motors.
In the above block diagram the Open Loop Speed control for induction motors is shown.
The system consists of the Rectifier, Filter, Three phase variable Frequency Inverter and induction motor.
The controlled rectifier converted the tree phase supply to a DC, the out put of the rectifier is a pulsing DC, there fore it is passes through the Filter, after the filter the DC voltage is feed to the variable frequency inverter ckt and the it supply to the induction.
There is no feed back in this system for the control purpose there it is called Open Loop control System.
Closed Loop Speed control for induction motors.
In the above block diagram the Close Loop Speed control for induction motors is shown.
The system consist of the Rectifier, Filter, Three phase variable Frequency Inverter, Feed back system and induction motor.
The main operation of the Closed Loop Speed control for induction motor is same as of the Open Loop system, In this system simply a feed back system is introduce to control for control purpose.
Monday, 9 March 2015
Static and Dynamic Control System
Static and Dynamic Control System
Static control systems
If the object of the control system is to maintain a physical variable at some constant value in the presence of disturbances, we call this system a] "Static control system" or a "regulator".
One example of a regulator control system is the speed control System on the AC power generators of power utility companies. The purpose of this control system is to maintain the speed of the generator at the constant value that results in the generated voltage having a frequency of 50 Hz in presence of varying electrical power loads.
Dynamic control system
The second class of control systems is the dynamic control system or servomechanism. Although this form was originally applied to a system that controller a mechanical position or motor, it is now often we to describe a control system in which a physical variable is require to follow, or track, some desired time function.
An example is the control system of a robot is which the robot hand is made to follow some desired path in space.
A second example of this type of system is an automatic aircraft landing system, which the aircraft follows, a ramp to the desired touchdown point. For example, large passenger aircraft can be landed automatically at many airports.
Ml (Multi Input)
In a control system when there are two or more inputs variable and one output variable it is known a Ml.
The control of the speed of motor there are two forces acting upon it.
1). Torque: -
Torque, which is controlled by the input voltage or current
2). DISTURBANCE: - (EXTERNALS).
Therefore there are two inputs variable and one output variable.
MIMO (MULTI INPUT MULTI OUTPUT)
When there are two or more variable input and two or more variable outputs this is called MIMO.
The Engine of An Aircraft
The input variables are fuel rate and propeller blade angle and output variable are turning speed of the engine and inlet temperature. Any variation in the inputs can effect the speed and the temperature of the engine.
SISO
"SISO stands for single input single output. In this system there are only one input variable and also only one output variable."
Draw the Block diagram of the Digital Gluco meter
Digital Gluco meter
Operation/ Working
Gluco-meter is stands for Glucose meter. This instrument is used to check the % value of sugar in the blood of a human body. It is a small digital meter with ON-OFF push button, screen indicate the readings, and a place to enter the blood soaked strip for testing the blood for sugar the different functions and readings of the result can be displayed on the screen. It can be give the result within a minute.
The Gluco Meter is Consists of Following Parts
Power supply section
The power supply section of digital Gluco-meter consists of four or more alkaline manganese button batteries which are non dangerous or harmful. This section is used for providing necessary power to other stages.
Light source
There is a light source, which may be an LED with a lens. The light is focused on test strip with the help of lenses.
Test strip
There-are test strip, which is' shown in block diagram. This is used to obtain the sample of blood. Every strip has a test pad (filter) on it. This test pad has a certain chemical on it. The test strip is inserted in the test strip guide meter. A suspended drop of blood is allowed to from and is applied to the yellow test pad and without spreading the drop and without touching the pad. The test pad should be completely covered.
Due to the chemical on the test pad, the blood drop is divided into different particles separately.
Optical sensor
There is an optical sensor. The light from the light source is passed through the test pad. This light passes through the test pad counting the glucose or sugar particles.
When optical sensor receives this differentiated light, it produces potential according to the counting of glucose or sugar particles in blood. The potential (voltage) is a measure of glucose quantity.
Pre-amplifier
The signal produced by optical sensor is applied to a pre-amplifier, which performs pre-amplification of the signal.
Final amplifier
The output of pre-amplifier is applied to the final amplifier, which further amplifies the signal.
Analog to digital converter
The amplified analog signal is applied to an analog to digital converter (ADC), which converts it into digital form.
Display unit
The digital signal is applied to the display unit, which display the reading on screen.
Reading unit
Reading in milligram per deciliter (mg/de) or mille mole /liter,
Control panel unit
There is a control panel unit, which has different buttons for various options i.e. (button for ON & OFF)
Application
1) It is specially used in medical field to determine the quantity of sugar or Glucose in blood.
Block Diagram of the CT Scanner
CT scanner
The CT Scanner is the abbreviation of computer tomography scanner. The invention of CT Scanner in 1970 was made possible by a previously established insight and development of the dedicated minicomputers.
The operation of CT Scanner can be described in following steps.
1) High voltage supply drives the x-ray tube that can be mechanically
rotated along the circumference of a gantry.
detectors, which are fixed in a place around the circumference of the
gantry in a large quantity.
the output of the detector scanner which is opposite to the x-ray
tube.
made by the computer.
cross the section of patient.
rotated along the circumference of a gantry.
detectors, which are fixed in a place around the circumference of the
gantry in a large quantity.
the output of the detector scanner which is opposite to the x-ray
tube.
made by the computer.
cross the section of patient.
2) Patient is lying in a tube in the center of gantry.
3) The X-rays passes through the patient and produces an image on
4) Microcomputer sense the position of tube in the gantry and samples
5) A calculation based on the data of a computer scan of the tube is
6) The O/P unit then produces a visual image of a transverse plane
7) The output may be displayed on the cathode ray tube or photographed
with a camera to produce a hard copy record.
Detector operation and construction: -
Detectors consist of ionization chambers filled with a gas such as xenon, sealed at both ends and having two conductors forming a capacitor on the sides.
A high DC voltage is applied to the capacitors an x-rays entry. The chamber ionizes the xenon item causing it to migrate to capacitor plate and causing a current in the high voltage load. This current is proportional to the radiation and is fed to the computer as data for computing the image.
The advanced model of CT scanner create image at an angle other than 90° by tilting the gantry.
Application
1) Its major application is in medical field. In medical, it is used to
Detect the injury in the human brain
2) It is used to detect inner wounds.
Thursday, 5 March 2015
Coaxial Cables
Coaxial cables used to conducts High frequency electrical signal in an inner core mostly used copper
or copper plated wire surrounded by an insulating wire and a enclosed by a protective
shield. Normally a coaxial
cables used
for video and CCTV distribution,
RF and microwave transmission and computer Networks and connectors.
Welcome Note
Welcome to Guru4Tech our team striving hard to provide
you all types of information(s) required by you to fulfill your lust for knowledge. Please have a tour of the site and see whether your desired purpose
is met or not.Your comments & suggestions are always welcome for the
improvement of the site.
Subscribe to:
Posts (Atom)