Tuesday, April 8, 2008


As the name implies it is an operational amplifier. It performsmathematical operations like addition,subtraction,log,antilog etc.. Themain reason for OPAMPS used over transistors is that transistor can onlyamplify AC while OPAMPS can amplify AC and DC. You can get good amplifier gain in OPAMPS. The most commonly used OPAMPS are 741 ,LM 324, LM 358N(both of them can also be used as comparator).

Comparator is also the same but with a diff being tat its digital so u have to two states high(5V) and low(0V).
Above figure shows the general ckt diagram of a comparator .If V1>V2 then Vout=+Vcc and if V1 if V1 is less than V2 then Vout is minus Vcc

Lm 324 has 4 such comparator(shown in figure1) them also known as Quad opamp.
LM 358N has 2 comaprator also known as bi opamp.

U can use two potentiometers(of 10 K prefarably) and put them across pin2 and pin 3 , and put an led in series with a resistance at pin 1 , when the voltage drop in pot 1 connected across pin 2 is low , u can c the led glow.

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