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Part 2: Operational Amplifiers
An operational amplifier is a very high gain amplifier. Op amps can be used in many different ways. Two of the most common uses are
An op amp has TWO inputs; one non-inverting (called the "+" input) and one inverting (called the "-" input). The voltage at the output ( Vo) depends on the DIFFERENCE between the voltage at the non-inverting input (V+) and the voltage at the inverting input (V-). Expressed mathematically,Vo = A.(V+ - V-) where A is the gain or voltage amplification of the op amp (typically 100000) The diagram below shows an op amp together with its circuit symbol.
N.B. Op amps must, of course, always have a battery or some other supply of energy connected to them. However, in many circuit diagrams the supply connections are not drawn. In the experiments which follow, use digital voltmeters. |
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