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    regarding amplification

    my problem is to amplify a 1V ac signal to 15 V AC signal with 1AMP current capacity.
    i started amplifing with OP-AMP and got 15 volt ac. but in order to get 1 amp. current capacity to for next stage. so i need the help for doing this.

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    Re: regarding amplification

    For low frequencies, you can use power OpAmp, for example L165 by SGS-Thomson (output current up to 3A). Vpp is typically 27V (decreases for higher output currents).


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    Re: regarding amplification

    Referring to standard parts from the lab stock, an OP with a complementary BJT voltage follower can be a simple solution. It's involving some cross over distortions, but usually sufficient for many applications. Power OPs have the advantage of bringing thermal shutdown and short circuit protection.


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    Re: regarding amplification

    sir, i got L165 power operational amplifier. while searching for the pin numbers , it's given top view of IC. what is the top view of IC. and for using this IC, shall i nneed to use diodes and capacitors as given in the data sheet?
    please give me the reply fast. thankyou sir.

    ---------- Post added at 16:34 ---------- Previous post was at 16:33 ----------

    sir, i got L165 power operational amplifier. while searching for the pin numbers , it's given top view of IC. what is the top view of IC. and for using this IC, shall i nneed to use diodes and capacitors as given in the data sheet?
    please give me the reply fast. thankyou sir



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    Re: regarding amplification

    I think you need to have amplification more than 10 so circuit is already there in your data sheet

    http://www.eng.yale.edu/ee-labs/mors...heets/1317.pdf

    I think that should work....

    Now related to purpose of those capacitors are decoupling capacitors and I think the diodes mention in your sechematic are for reverse current conduction ....i.e. they will be operating in negative cycles...

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    Re: regarding amplification

    my doubt is that , in the pin connection diagram that is given in datasheet is front view of op-amp or back view of op-amp. i am confused in getting pin numbers. in the diagram it is given that top view. what is the meaning of top view


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    Re: regarding amplification

    Pin 1 of the IC will have a notch or dot near it. Count each pin incrementally anti-clockwise.


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    Re: regarding amplification

    this structure is not like IC741 and notch is given in pin 3. that is in the middle. that's why i got the doubt



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    Re: regarding amplification

    That is prity simple -

    Just check you chip the Pin connection are also given in chip datasheet

    refer this picture

    Good Luck

    Click image for larger version. 

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    Re: regarding amplification

    Does this help:

    L165 Pinouts



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    Re: regarding amplification

    That's top side, pin 1 is left.



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    Re: regarding amplification

    Quote Originally Posted by gollapudi View Post
    my doubt is that , in the pin connection diagram that is given in datasheet is front view of op-amp or back view of op-amp. i am confused in getting pin numbers. in the diagram it is given that top view. what is the meaning of top view
    Top view is when you look at it from the side where the IC number is printed. The pin numbers start from the left. Like this -



    Ah, didn't mean to duplicate your post, FvM. I left the reply window open while I had supper, then came back and finished the reply and posted without checking.


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    Re: regarding amplification

    sir, by mistake i shorted the output terminals of amplifier. so i have doubt weather it will work further or not. wheather the L165 having short circuit protection or not? please give me reply



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    Re: regarding amplification

    The datasheet is quite clear about SOA protection, I think. It's sensitive against reversed output voltage however, thus the protection diodes shouldn't be omitted.



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    Re: regarding amplification

    SOA stands for Safe Operating Area which defines a combination of voltage and current that is safe for a device. Even if neither the maximum voltage nor current is exceeded, a device may be damaged if a certain level of voltage and current combination is exceeded.

    The L165 has internal protection against overheating and exceeding of the SOA and this may be regarded as one kind of short-circuit protection. However, no protection is 100% foolproof. The best way to find out if your IC is still Ok is to run it again and see if it's working normally.



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    Re: regarding amplification

    sir,
    is it possible to check the IC L165 , my measuring the resistance between the terminals. any two L165 IC's are going to having the same resistance between the terminals or not? my doubt is that resistance between terminals changes for two different L165 IC's.



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    Re: regarding amplification

    Look at this way....you are using operational amplifier....so there will be high input impedances and low output impedance....this means the following
    1) Impedance between non inverting pin and inverting pin or non inverting pin / inverting pin and Vs- will be very high
    2) Impefance between output pin and and VS- will be very low
    3) and Impedance between Vs+ and Vs- will be moderate....

    Also there will be componet variation also measuring condition variation when you are using two different L165 IC.....So you will see the variation in the resistances .....but they will not change drastically.....like one IC give you resistance of 1Kohm and second IC will give you 1Mohm.....

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    Re: regarding amplification

    when i am giving 15 volts(+ and -ve), before connecting to L165 it is giving 15 volts. but after supply is givowen , the voltage at positive terminal goes less than 15 volts( it shows 2 volts only), and the negative terminal showing 15 volts. what may be the reason for this? please give me reply. and my IC is getting heating also.



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    Re: regarding amplification

    Please check with other IC....I think present IC that you have may be faulty.....Also just remove the diodes in case you are connected ......and check the voltage at the pins.....some time there meight be faulty and reverse conduction too cause...

    Good Luck
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    Re: regarding amplification

    Quote Originally Posted by gollapudi View Post
    my problem is to amplify a 1V ac signal to 15 V AC signal with 1AMP current capacity.
    Wouldn't it be simpler to buy a kit for a 15 - 20W audio amplifier?
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