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Posted by BitesizePhysicsTeacher (U15165682) on Saturday, 26th January 2013
The circuit diagrams for operational amplifiers can be a bit daunting to look at, and there will be a couple of other posts after this one to deal with the more complex types of circuits that sometimes come up in papers.
The simplest type of op-amp circuit is the inverting mode operational amplifier -
+ only one input voltage, V1 , to the inverting input (-), via resisitor R1
+ non-inverting input connected to zero volts (i.e. V2 = 0 V)
+ feedback resisitor, Rf, connects output, Vo , to the inverting input
circuit diagram can be found here - www.bbc.co.uk/bitesi...
For all inverting mode op-amps, the output is given by the formula -
Vo = - Rf/R1 x V1
** N.B. the output voltage always has the opposite sign to the input voltage **
** if the calculated value of Vo is greater than Vs, the supply voltage, then the output will SATURATE, as no amplifier can produce a voltage larger than its supply.