The operational amplifier , Other Engineering

The operational amplifier :

The integrated circuit operational amplifier is one of the most useful and versatile electronic devices available today.  The name 'operational amplifier' is not new; it refers to a type of amplifier originally used in analogue computing to perform mathematical operations - e.g. multiplication or division by a constant.  The modern integrated circuit device can be adapted (by feedback) to perform most general-purpose amplifier duties, as well as its use in mathematical operations. 

The Op Amp can consist of many stages of amplification to ensure high gain, and will be arranged to have two input terminals, two power supply terminals and an output terminal.  In addition it will normally have terminals for setting the output to zero when the input is zero.

The Op Amp consists of a transistor circuit of considerable complexity, which has been found so useful that the whole circuit is manufactured on a single piece of silicon, fitted with input and output leads, and covered in plastic.  It is the first "Integrated Circuit", and can be treated just as if it were a new component.  Figure shows a type 741 Op Amp and circuit.

24_operation amplifier.png

In the Op Amp, two pins are marked supply + and supply  - and are connected to the amplifiers power supply.  The device also has two inputs, the "Inverting input" (VI) identified by a negative symbol.  A "Non inverting input" (VN) identified by a positive sign and a single output (VO).

Note:  The negative/Positive signs on the inputs does not mean that negative/positive signals are applied, but identify the inverting and non-inverting terminals.

The VI, VN and VO are the values of the voltages applied to the inputs and obtained form the output.  These voltages are joined by the equation:

                  VO = AO (VN - VI)

Here we have a slight problem.  Voltages are measured between one point in a circuit and another.  Usually one point is the negative or zero line.  When calculating VN & VI it does not matter were the reference is as long as it is the same for both voltages.  When we obtain the output VO we need to know the reference point used by the Op Amp.  This is not the zero line but a voltage halfway between the positive supply and the zero line.

The other unknown quantity in the equation is AO, the "Open Loop Gain".  This gain is constant for each particular Op Amp and is the ratio between two voltages.  Open Loop gain in Op Amps is normally 105.

Posted Date: 9/14/2012 6:07:51 AM | Location : United States







Related Discussions:- The operational amplifier , Assignment Help, Ask Question on The operational amplifier , Get Answer, Expert's Help, The operational amplifier Discussions

Write discussion on The operational amplifier
Your posts are moderated
Related Questions
Mergers Acquisition Mergers and acquisitions involve complex accounting treatment a merger, defined as amalgamation in India, involves the absorption of the target company by the

Commercial buildings - fire protection engineering: The term 'commercial buildings' refers to any buildings that are not residential buildings and that do not fall under the m


Here, it is assumed that the crack is effectively longer than the value measured on the side of the specimen. If one assumes that it is longer by an amount Δ, then the new crack le

5. From the following details you are required to make an assessment of the average amount of working capital requirement of Hindustan Ltd. Particulars Average period of credit E


JFET OPERATION Figure shows the operation of a JFET. The JUGFET has a physical structure that can be represented by the diagram shown in Figure. In Figure, if the N-Ty

BASIC ENGINE DESIGN CONSIDERATIONS Effect of engine size: The two parameters involved are the diameter, d and stroke, L of the engine. The effect of doubling each of this

I am preparing for a seminar ... but I am searching for a very good topic. Can you help me to get a topic in wireless communication . i want to know what are the latest technologie

Sprinkler system - fire protection engineering Sprinkler systems may be installed in a building to achieve a number of different objectives.  Very often the primary reason for