|

Hartley Oscillator


Aim:


To study the operation of Hartley Oscillator

Apparatus:


1.     Analog board AB68
2.   DC Power Supplies +12V from external source or ST2612 analog lab
3.   Oscilloscope 20 MHz, Caddo 802 or equivalent
4.   2 mm patch cords

Theory:


The Hartley oscillator is one of the simplest and best known oscillators and is used extensively in circuits, which work at radio frequencies.  The transistor  is in voltage divider bias which sets up Q-point of the circuit. The output voltage is fed back to the base and sustains oscillations developed across the tank circuit, provided there is enough voltage gain at the oscillation frequency. The resonant frequency of the Colpitt oscillator can be calculated from the tank circuit used. We can calculate the approximately resonant frequency as
1
ResonantFrequency(fr) =
2π√LT C
Here, the Inductor used is the equivalent Inductance. In Hartley oscillator the circulating current passes through the series combination of L1 and L2. Therefore equivalent Inductance is,

LT = L1 + L2 + 2M
√
 
Where, M is the mutual inductance between two inductors.


M = K    L1L2
Where, K is the coefficient of coupling, lies between 0 to 1. The coefficient of coupling gives the extent to which two inductors are couple.

Circuit Diagram:



Procedure:

1.     Connect +12V dc power supplies at their indicated position from external source or ST2612 Analog Lab.
2.   Connect a patch cord between points a and b and another patch cord between point d and ground.
3.   Switch ON the power supply.
4.   Connect oscilloscope between Vout and ground on AB68 board.
5.   Record the value of output frequency on oscilloscope.
6.   Calculate the resonant frequency using equation mentioned.
7.    Compare measured frequency with the theoretically calculated value.
8.   Switch off the supply.
9.   Remove the patch chord connected between points a and b and connect it between points a and c.
10.   Remove the patch cord connected between points d and ground and con- nect it between point e and ground.
11.     Follow the procedure from point 4 to 7.

Result:

•    When patch cords are connected across a and b.
Practically calculated Output frequency (on CRO): 1.055 MHz Theoretically calculated values:
LT : 2.078 x 10−5 H
Resonant frequency (fr): 1.1038 MHz

•    When patch cords are connected across a and c
Practically calculated Output frequency (on CRO): 310.6 KHz Theoretically calculated values:
LT : 2.278 x 10−4 H
Resonant frequency (fr): 334 KHz

Read More
|

Colpitt’s Oscillator


Aim:

To study the operation of Colpitt’s Oscillator

Apparatus:


1.     Analog board AB67
2.   DC Power Supplies +12V from external source or ST2612 analog lab
3.   Oscilloscope 20 MHz, Caddo 802 or equivalent
4.   2 mm patch cords

Theory:


Oscillators are circuits that produce specific, periodic waveforms such as square, triangular, sawtooth, and sinusoidal. Two requirements for oscillation are:

1. The magnitude of the loop gain AvB must be at least 1, and
2.            The total phase shift of the loop gain AvB must be equal to 0o or 360o.  If  the amplifier causes a phase shift of 180o, the feedback circuit must provide an additional phase shift of 180o so that the total phase shift around the loop is 360o.

The Colpitt oscillator is  one of  the  simplest and best known oscillators and  is used extensively in circuits, which work at radio frequencies. The transistor is in voltage divider bias which sets up Q-point of the circuit.In the circuit note that Vout is actually the ac voltage across C2. This voltage is fed back to the base and sustains oscillations developed across the tank circuit, provided there is enough voltage gain at the oscillation frequency.

The resonant frequency of the Colpitt oscillator can be calculated from the tank circuit used. We can calculate the approximately resonant frequency as
1
ResonantFrequency(fr) =
2π√LC
Here, the capacitance used is the equivalent capacitance the circulating cur- rent passes through. In Colpitt oscillator the circulating current passes through the series combination of C1 and C2. Therefore equivalent capacitance is,

C equivalent) =   C1C2
(                                         C1 + C2




Procedure:

1.     Connect +12V DC power supplies at their indicated position from external source or ST-2612 Analog Lab.
2.   Connect a patch cord between points a and b and another patch chord between points d and g1.
3.   Switch ON the power supply.
4.   Connect oscilloscope between points f and g2 on AB–67 board.
5.   Record the value of output frequency on oscilloscope.
6.   Calculate the resonant frequency using equation mentioned.
7.    Compare measured frequency with the theoretically calculated value.
8.   Switch off the supply.
9.   Remove the patch chord connected between points a and b and connect it between points a and c.
10.   Remove the patch chord connected between points d and g1 and connect it between points e and g2.
11.     Follow the procedure from point 4 to 8.
12.   Connect +5V supply instead of +12V supply ly and follow the procedure from point 2 to point 11.

Result:

•    When patch cords are connected across C1 and C2
Practically calculated Output frequency (on CRO): 1.073 MHz Theoretically calculated values
Cequ: 14.98 nF
Resonant frequency (fr): 1.18  MHz Output voltage amplitude : 1.90 V (Vp-p)


•    When patch cords are connected across C3 and C4
Practically calculated Output frequency (on CRO): 1.76 MHz Theoretically calculated values
Cequ: 4.71 nF
Resonant frequency (fr): 2.12  MHz Output voltage amplitude : 3.58 V (Vp-p)





Read More
|

Pankaj Joshi On Science And Spirituality



Read More
|

Digital Electronics - Introduction and Important

Digital simply means that signals are sent in 'chunks' instead of a steady stream (analog)
Read More
|

Want To Physics ? Buy and Read This Best Books


Buy Online Books and receives extra Cashback for this websites
1.Click to image and you are going amazon official website
2.Purchase and buy the book
3. Send your bill and Paytm No on Whatsapp no 9586551131
4. Within 24 Hours You received Cashback up to Rs 100 or 2% of original price

Six Easy Pieces: Essentials of Physics Explained by Its Most Brilliant Teacher  Six Not-So-Easy Pieces: Einstein's Relativity, Symmetry, and Space-Time
 
Alex's Adventures in Numberland
Physics of the Impossible: A Scientific Exploration of the World of Phasers, Force Fields, Teleportation and Time Travel

Quantum: Einstein, Bohr and the Great Debate About the Nature of Reality
In Search Of Schrodinger's Cat: Updated Edition

The Elegant Universe: Superstrings, Hidden Dimensions and the Quest for the Ultimate Theory
Mathematical Methods for Physics and Engineering: A Comprehensive Guide

Fundamentals of Physics
Div, Grad, Curl, and All That: An Informal Text on Vector Calculus

The Visual Display of Quantitative Information
Relativity: The Special and the General Theory
Read More
|

Essay Writing compition by Department of Atomic energy ( DAE )

The Department of Atomic Energy (DAE) invites essays on Nuclear Science & Technology as per following details written in any official Indian language or in English from regular full time students studying for graduation in India (after 10+2), in any discipline, in an Indian university or an institute deemed to be a university.

Topics

Long Term Energy Security and Sustainable Development in India – Role of Nuclear Energy
Advancement in Radioisotopes and Isotope Technology
Science and Technology of Plasma for Mankind and Safe Environment

Essay Structure

Maximum of 350 words. Highlight the multifarious achievements of DAE in basic sciences and nuclear technology development and their use in overall societal development in the country. Detailed essay: Maximum of 1500 words. Conclusion: Maximum of 150 words. Entire essay not to exceed 2000 words.

Prizes

The prizes for each topic are as follows:

First Prize: Rs. 25,000 x 3 = Rs. 75,000
Second Prize: Rs. 20,000 x 3 = Rs. 60,000
Third Prize: Rs. 15,000 x 3 = Rs. 45,000
Consolation: Rs. 7,000

How to Send

The essay should be sent directly by the contestant, along with bonafide studentship certificate from the Principal of his/her College/Institute.
The participant shall write his/her Name, College/Institute and Residential address with Contact no and Email-ID of the Student as well as the Institute to be provided on a separate detachable sheet to communicate the results of the written essay.

The essay shall be sent to:
Assistant Personnel Officer
Public Awareness Division, Dept of Atomic Energy,
Government of India, Anushakti Bhavan,
CSM Marg, Mumbai – 40000

Last Date for Receiving Essay: Aug 2
Read More
|

Best Books for Physics for Acadimics


Introduction to Electrodynamics by David J. Griffith
Modern Physics by Arthur Beaser 



Classical Mechanics

Classical Mechnics by J.C. Upadhyay


Classic Mechnics



Read More
|

NASA MASS MISSION




Engineers at NASA's Jet Propulsion Laboratory in Pasadena, California, have installed the SuperCam Mast Unit onto the Mars 2020 rover. The instrument's camera, laser and spectrometers can identify the chemical and mineral makeup of targets as small as a pencil point from a distance of more than 20 feet (6 meters).
SuperCam is a next-generation version of the ChemCam instrument operating on NASA's Curiosity Mars rover. It has been developed jointly in the U.S., France and Spain. Once France delivered the last piece of flight hardware, the instrument was fully integrated on the Mars 2020 rover on June 25, 2019, in the Spacecraft Assembly Facility's High Bay 1 clean room at JPL.
"SuperCam has come a long way from being a bold and ambitious idea to an actual instrument," said Sylvestre Maurice, the SuperCam deputy principal investigator at the Institut de Recherche en Astrophysique et Planétologie in Toulouse, France. "While it still has a long way to go — all the way to Mars — this is a great day for not only SuperCam but the amazing consortium that put it together."
Mars 2020 scientists will use SuperCam to examine Martian rocks and soil, seeking organic compounds that could be related to past life on Mars.
"SuperCam's rock-zapping laser allows scientists to analyze the chemical composition of its targets," said Soren Madsen, the payload development manager at JPL. "It lets the Mars 2020 rover conduct its cutting-edge science from a distance."
Also to be installed in the next few weeks is Mars 2020's Sample Caching System, which includes 17 separate motors and will collect samples of Martian rock and soil that will be left on the surface of Mars for return to Earth by a future mission.
Mars 2020 will launch from Cape Canaveral Air Force Station in Florida in July of 2020. It will land at Jezero Crater on Feb. 18, 2021.
NASA will use Mars 2020 and other missions, including to the Moon, to prepare for human exploration of the Red Planet. The agency plans to establish a sustained human presence on and around the Moon by 2028 through NASA's Artemis lunar exploration plans.
SuperCam is led by Los Alamos National Laboratory in New Mexico, where the instrument's Body Unit was developed. That part of the instrument was installed in the body of the rover in May and includes several spectrometers, control electronics and software. The Mast Unit was built with contributions from numerous academic laboratories in France, led by the French space agency Centre National d'Études Spatiales, and includes the high-powered laser, a telescope, a camera, an infrared spectrometer and a microphone. Calibration targets on the rover deck are provided by Spain's University of Valladolid.
JPL is building and will manage operations of the Mars 2020 rover for the NASA Science Mission Directorate at the agency's headquarters in Washington.
If you want to send your name to Mars with NASA's 2020 mission, you can do so until Sept. 30, 2019. Add your name to the list and obtain a souvenir boarding pass to Mars here: 
https://go.nasa.gov/Mars2020Pass
For more information about the mission, go to:
https://mars.nasa.gov/mars2020/
News Media Contact
Andrew Good
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-2433
andrew.c.good@jpl.nasa.gov
Alana Johnson
NASA Headquarters, Washington
202-358-1501
alana.r.johnson@nasa.gov
To apply mass mission

 Click Here


Read More
Subscribe to: Posts (Atom)