SUMMARY

Monday, 17 September 2018

12:13 PM

Machine generated alternative text: Operational Amplifiers (Op Amps) are active elements. — They can be modelled as a voltage-controlled voltage source. Op Amp circuits are designed to perform mathematical operations on input signals. They are manufactured in the form of Integrated circuits (ICs). From the 8 pins of the Op Amp IC, we are only interested in 5 of them. • — Inverting input VI (pin 2). Non-inverting input (pin 3). Output vo (pin 6). Positive power supply V + (pin 7). Negative power supply V - (pin 4). • The output of the Op Amp in open-loop is proportional to the differential input voltage. = (122 — VI), where A is the open-loop gain (in the range of 105 to 108). vo = Avd • Op Amp circuits should be operated in the linear region to avoid saturation of the output (output should not exceed the voltage of power supply IVccl). —Vcc

 

Machine generated alternative text: • An Ideal Op Amp has the following properties: Open-loop gain close to infinity, A co. Input resistance close to, infinity Ri oo O (open circuit). Output resistance close to zero, Ro 0 Q (short circuit). The currents into both terminals are zero. The voltage across the input terminals is zero (if there is negative feedback). I'd = 1'2 -VI = 0 or VI = 1'2 • Use Nodal analysis to solve and analyse Op Amp circuits. KCL at input nodes to calculate vo. Once output voltage vo is found, use KCL at output node to find output current io(if needed). Gain of the circuit = ratio of output to the input (vo / Vi). Op Amp circuits are mostly used in negative feedback configuration. The output is fed back to the inverting input via feedback resistor RT. The inverting input and non-inverting input are connected to either ground or a source via input resistor RI.

 

Machine generated alternative text: Inverting amplifier Noninverting amplifier Integrator vo(t) = Voltage follower Summer VI V n; Vl+n-V2+n-V3 Difference amplifier n-0'2 — VI) 1 RC Di fferentiator vo(t) = —RC dt

 

 

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