06-10-2012, 04:18 PM
Some Applications of Operational Amplifier
Some Applications of Operational Amplifier.pdf (Size: 126.68 KB / Downloads: 126)
Introduction
OPAMP is an eight-pin integrated circuit (IC
741 readily available in markets) consists of an
inverting input terminal (pin 2), a noninverting
input terminal (pin 3) and an output
terminal (pin 6). However the circuit inside
OPAMP IC is very much complicated. It
consists of a monolithic silicon IC containing
17 transistors (6 pnp and 11 npn), 10 resistors,
4 diodes and 1 capacitor. To activate this
OPAMP ±9 V to ±12 V dc power-supplies are
connected (pins 4 and 7). The specifications of
this OPAMP are1: (i) Infinite input resistance.
(ii) Small output resistance. (iii) Infinite open
loop gain. (iv) 0° to 180° phase shift.
Experimental
In the circuit diagram shown in Figure 1 output
is connected to an ordinary table voltmeter
with desired range (0–10V, 0.1V). To increase
accuracy high impedence meters with different
ranges may also be used. The non-inverting
input terminal of OPAMP (IC 741) described
earlier is directly grounded and the inverting
input is connected to the hot junction of the
copper-constantan thermo couple (called two
junction thermo couple) after the input carbon
resistor R.3 The end of the cold junction is
grounded.