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shaiqbashir

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Posts posted by shaiqbashir

  1. Hi guys!

    well! i want a 5ohm-20watt power resisitor. First of all please tell me that whether this resistor is available , i mean that is this a standard resistor. And im having some problems finding this in the market. So please can anybody tell me some alternatives to this. I have heard from one of my friends that we can make a resistor according to our required resistance and wattage by using a coil wire by using the formula:

    R=pL/A

    well! by this i can find a required resistance but how to find a coil of the required power. that is 20 watts.

    ur early reply shall be highly appreciated./

    take carez

    Regards,

  2. thanks a lot Audioguru!


    but one question of mine still remains intact. What should be the values of Cin and Cout in order to make it suitable for 5.2V @ 6A.

    should i go with 10uf because datasheet says that for Cout, 10uf is a good starting point.

    but i didnt find any clue regarding Cin.
    can u tell me what function this Cin is performing?
    Thanks in advance


    take carez

    Regards,

  3. Hi guys!

    thanks for ur tremendous help.

    Well! as far as Ante advice is concerned, i have checked the datasheet of Max724/726 and found it really good. I have attached below an application diagram of it i found in that datasheet. What i want to ask here is this, that you can see in the application diagram that it is providing 5V at 5A. If i have a requirement of around 5.2V at 6A, will this diagram work????
    max.JPG

    Secondly, i have found myself a high current voltage regulator named as MSK5012. I have also attached an application diagram of it below. This was also found in the datasheet. Now considering the same requirements as above i.e. 5.2V at 6A, what will be the value of Cin and Cout? How current can be adjusted in this IC.

    [img width=680 height=485]http://www.geocities.com/shaiqbashir/MSK5012.JPG

    Please keep this thing in minds that i have a 12V 5Ah DC battery as a source.

    Your early reply shall be highly appreciated.

    Thanks in advance!

    Regards.




  4. HI Guys!

    well! my dear friends!

    Im making a robot. In which i will be requiring 5V for a motor. I have a 12VDC, 5AH battery.

    Now how i will supply 5V to a motor from a 12V battery. Should i use a regulator 7805. Will it be able to handle an input voltage of 12V??????

    and one thing that i was also thinking is this that first i use 7809 regulator to regulate the battery voltage to 9V and then use 7805 to further regulate that 9V to 5V.

    And what about the curent ?

    i mean my stepper motor requires 1.4A per phase of current. so It will be around 5.6A total requriement. Will the regulator be able to supply such a high current.

    If not what should be the best method to do that.

    I shall be thankful to u if u will make an eary reply

    thanks in advance

  5. Hi Guys!


    well i want to ask you about the voltage ratings of an electrolytic capacitpr. I want to know that why these capacitors are categorized by their voltages. Like there is a capacitor of 100uF of 12V and there is a capacitor of 100uF of 50V. WHat is the difference between the two.

    Secondly, in a certain circuit, there is to be used a 0.33uF capacitor of 12V. While in my market, 0.33uF of 50V is avaialable. Can i use the 50V capacitor in the place of 12V one. If not then what should be the replacement. Secondly, please tell me that if a capacitor of a value is not avaiable in the market, then how should we search for its replacement.

    Thanks in advance!

    Regards,

  6. Hi Guys!

    well ! i want to use a single op-AMP with a +-15V DC supply. Remember that no other external DC supply is to be used except that.

    and i want to get the following output.

    Vo=Vi + 5

    now what i have in my mind is this. That i make a voltage follower that is a unity gain amplifier. and i would get as a result:

    Vo=Vi

    and then for getting 5V more, i think i want to use a voltage divider with 1Mohm and 2Mohm resistor to reduce the 15V supply voltage to 5V and make its path to the output.

    that is, 5V will be continouously supplied to the output, no matter whether the input Vi is present or not. When the input Vi will be provided , it would give me (Vi+5)  as an output.


    Please make me correct if im wrong here. and help me in getting the required answer.

    I shall be very thankful to u for this act of kindness.

    Take carez and Good Bye!

  7. Hi Guys!

    well!

    im just a bit confused here.


    i want to ask you a question:

    just have a look at the fig below which i have posted. You can see a load resistor "RL". my question is that whenever i studied this inverting configuration of opAmp, there is no load resistor given for it. So, now when i have to find the equation of its gain , with a load resistor, do u think that it will change from the one without a load resistor.

    i know the gain equation which will come without load resistor. but what about tha equation with load resistor.


    now do u think that with the load resistor RL, this gain equation will change?

    thanks in advance:


    opamp_1.JPG

  8. HI audioguru!

    sorry if i have violated the rules here.


    Okz

    now lets get back to the 1st circuit whihc you have presented. I remember that t his circuit u recommended to me at that time whihc i was able to make successfuly by the grace of God.


    okz


    now i have some questions in my mind in order to get it understood.


    1) First please explain me that why you have used this 2.7ohms resistor with 0.1uF. what sort of function is this. I think it is some sort of feedback. Then but this capacitor is looking neither bypass nor coupling. Please explain it.


    2) and then plz tell me that why you have connected 1000uf capacitor in parallel with the power supply. and why u have selected this value of capacitor? i mean if i ever want myself to select the value, what things should i keep in my mind?

    3) What is the function of VR1, when in my circuit i vary this, the loudness increases with a huge distortion sound at its peak.


    I shall be thankful to u if u would explain me these points

  9. Hi guys!

    i really donot know what sort of laziness you people have seen in my post. There are lots of GURUs roaming here, so if i would discuss with them about my project, what is so odd about it then.

    And please keep this thing in ur mind u all ELECTRONICS GODs, i never ever want u people to do my homework, i have myself decided what and where i want to go, just asking for some ideas, i guess this is the reason why this specific board has been made named as ELECTRONICS PROJECTS DESIGN IDEAS.

    Im thankful to Mr. Audioguru to specify quite a precious direction to go into.

    And i would like to thank Mr. Doctor and Mr. Ante to share their precious compliments with me.

    I still beleive on the following statement strictly:

    Hardwork + Prayers = Success

  10. Hello Guys!

    thanks a lot for your precious hot discussions. But i think that i should have clarified question 1 MORE.

    Well my dear friends, im just asking you in terms of entropy generation that which energy is more useful. Obviously, we cannot use electrical energy everywhere. But once i heard somwhere that electrical energy is an energy in whihc the entropy generation is least as compared to other forms of energy. That is the reason why its efficiency is very high. Is it correct? if not then please tell me why it is more useful.


    I hope that you people love to help others.

    Thanks in advance

    Good Bye!

  11. hi Guys!

    well! i want to ask you people two very important questions:


    1) Why electrical energy is prefered over other forms of energies?

    2) What are electrical machines. If you think that electrical machines convert electrical energy into another form of energy or vice versa, please keep this in mind that a transformer is also called an electrical machine and that doesnot perform any conversion of energy in different forms.


    Thanks in advance

  12. Thanks a lot audioguru!

    As a final conclusion plz check out my following lines whether they are correct or not:

    A negative feedback is used to decrease the HIGH GAIN of an Op-AMP to a suitable value. Because the open loop gain of an Op-Amp is so high that even the noise signals can be amplifiied to an extent that can saturate the Op-AMP. It is not possible with a negative feedback to work like autmatic gain control. The output can be clipped off if there would be a drastic change in the input signal beyond the limits provided by the supply and the safety of negative feedback.

    Thanks once again!


  13. If you feed it about 1.2V or more then its output will be clipped at about 11Vp-p.


    Hi Audioguru!

    thanks for your help. But im still having some problems in understandin your above quoted line.

    what do u think if a change of 1.2V occurs in the input signal., it gets clipped at the output. Now dont u think that negative feedback gets failed here. Or should i say that this will damage our load as well. Where is the stabilized gain then?

    is it only for some limits? suddenly a change occurs, and the speaker gets blast. Is it not possible to save it for 1.2V input as well. If yes then how?

    Thanks in advance
  14. Hi Guys!

    welll! taking an example of an OP-AMP, i want to ask you that it it said that a negative feedback is used to

    1)stabilize the voltage gain even if there occurs some change in the input signal voltage.

    2) to decrease the gain of the OP-AMP so that it cannot go into the saturation regions.

    2) point is clear to me as i know the formula of close loop voltage gain

    Vcl=1+ Rf/Ri

    .

    This function i can understand that a part of output voltage is given to inverting terminal and it gets subtracted from the input and the gain decreases.

    but what i didnt get is how a negative feedback works to stabilize the voltage gain by bearing all the unwanted changes in the input signal voltage.

    Please explain me this phenomenon. I will appreciate if you would put some detail here.

    Thanks a lot in advance

  15. Hi Guys!

    well! i have seen this circuit over some site.

    telconf.JPG

    this circuit will enable one person to talk to two different persons on different telephones simultaneously. I can explain it like this

    suppose that "A" calls "B", B recieves the call and puts it on hold and then dials C on another telephone and puts it on hold too and then he just closed switch 1 and 2 and then they can talk simultaneously.

    Now as you can see in the diagram, it is given the left side will be connected to TIP and RING and the right side is also connected to TIP and RING. I want to know how to connect this.

    in a telephone wire i know

    there are four wires actually

    TIP
    RING

    TIP
    RING

    are they talking about them. How i have to connect the circuit to it.,

    Thanks a lot in advance

  16. Hi audioguru!

    thanks for that valuable information. Now here i want to point out one thing that where is the laser diode in this circuit?

    there is a simple laser torch 3V powered. So if the circuit is supplying it 3.8V then i think it should work. Please explain this point.

    Secondly! i will be very very thankful to you if you would tell me the difference between DC negative feedback and AC negative feed back.  ???

    Thanks a lot once again!

    Regards,

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