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Op amp 741 or Operational Amplifier 741 IC

The op amp is an electronic device, that behaves like a voltage controlled voltage source.
The op amp is an element, which can perform some basic mathematical operations like, addition, subtraction, multiplication, division, differentiation and integration. This is why this element is named as operational amplifier or in short op amp.
An op amp is a complex electronic device, which consists of resistors, capacitors,transistors and diodes. It is commercially available in integrated circuit form. Most commonly available and used op amp IC is IC 741. Op amp 741 is 8 pins IC.

  1. Pin 1 is balance pin
  2. Pin 2 is inverting input
  3. Pin 3 is non inverting input
  4. Pin 4 is negative power supply pin
  5. Pin 5 is balance pin
  6. Pin 6 is output pin
  7. Pin 7 is positive power supply pin
  8. Pin 8 does not have any connection
Hence, op amp 741 has two input terminals one output terminal. pin 2 and 3 are input and pin 6 is output. ic 741 pin configuration The circuit symbol of op amp 741 is shown below. circuit symbol of an op amp In an op amp symbol, + sign is marked on non-inverting input and - sign is marked on inverting input. When an signal is applied to the inverting input pin, the output will appear in opposite polarity. When an signal is applied to the non inverting input, the output will appear in same polarity as input. The equivalent circuit of an op amp is drawn below. equivalent circuit of an opamp The output of an op amp is a voltage controlled voltage source with a resistance R0 in series with it. The input resistance Ri exists between inverting and non-inverting input. Ri is the Thevenin equivalent resistance between input terminals. Similarly, output resistance is the Thevenin equivalent resistance seen at output. The input voltage of an op amp is the difference of the voltages applied at input terminals. This is called differential voltage and it is generally denoted as Where v2 and v1 are input voltages.
An op amp multiplies this differential voltage with the gain A. This gained differential voltage Avd, then appears at the output terminal. This is known as open loop voltage gain.

The typical parameters of a 741 op amp is furnished in the table below,

ParametersTypical RangeIdeal Value
Open Loop Gain(A)105 to 108
Input Resistance(Ri)105 to 1013
Output Resistance(Ro)10 to 1000
A typical range of supply voltage in 741 op amp is, The output of an op amp can not cross this range of supply voltage. That means, output voltage v0 ranges from -Vcc to +Vcc

If the supply voltage is denoted by Vcc in an op amp then, mathematically we can write, That means, output voltage v0 of an op amp cannot reach below –Vcc and above Vcc. Inside this range v0 is linearly proportional to the input differential voltage vd. This can be graphically represented as, An op amp is intended to be operated in that linear region.



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