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Electronicdevices2
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EXPERT SYSTEMS AND SOLUTIONS
Email: [email protected]@yahoo.comCell: 9952749533
www.researchprojects.info PAIYANOOR, OMR, CHENNAI
Call For Research Projects Final year students of B.E in EEE, ECE, EI, M.E (Power Systems), M.E (Applied
Electronics), M.E (Power Electronics)Ph.D Electrical and Electronics.
Students can assemble their hardware in our Research labs. Experts will be guiding the
projects.
OPAMP APPLICATIONS
Session-12
PRAKASH BISWAGAR
Asst.Professor, E&C Dept.
RV College of Engg.
Bangalore
ACTIVE FILTERS
• Filters are frequency selective networks
• Used in Communications
• Can be active or passive
FILTERS BASED ON FREQUENCY
(i) Low pass filter (LPF)
(ii) High pass filter (HPF)
(iii) Band pass filter (BPF)
(iv) Band stop filter(BSF)
(v) All pass filter
REALIZATION OF FILTERS
1. Butterworth filters
2. Chebyshev filters
3. Elliptic filters
4. Bessel filters
BUTTERWORTH FILTERS
• Named after the inventor “BUTTERWORTH”
• No ripple in the pass/stop band
• Have large transition width
• Filter characterized by system transfer function
• Where Pn(S) = Butterworth polynomial
• S = Complex variable = σ +jω
• Order of the polynomial indicates the order of the filter
• RC N/W used for filtering action
• R1 & R1’ used for gain adjustment
• OPAMP is configured in non-inverting model
LIMITATIONS OF BINARY WEIGHTED RESISTORS
(1) As the resolution increases, the resistor value increases
(2) The accuracy is low, since depends on resistor values.
R-2R LADDER TYPE DAC
• Uses only two values of resistors
• Overcomes the limitations of Binary weighted DAC
• OPAMP is connected in inverting mode
• Each digital input is applied through R-2R network and VRef
ADC’s• Converts analog signal into digital data• Used in Data acquisition systems & Digital
instruments etc
TYPES OF ADC
1.Counter type ADC
2.Successive approximation ADC
3.Flash or parallel converter type ADC
4.Integrated type ADC’s
(Single slope & dual slope)
COUNTER TYPE ADC
• Initially the counter is cleared• The analog signal is applied to one of the
inputs of the comparator• Counter o/p is converted into analog, by the
DAC• The DAC O/P is compared with the incoming
signal• Conversion stops when digital O/P >Incoming
signal
SAR ADC
• Widely used
• Similar to Counter type ADC except that ,a SAR is used
• SAR acts as programmable Up/Down counter
• Completion of conversion , triggered by a change in the state of the comparator
• Much faster than the counter type
FLASH ADC• For n-bit digital word, 2n-1 comparators are
required
• The analog sample is simultaneously applied to one input of all the comparators
• Other input to the comparator is a DC voltage derived from the pot. divider N/W
MAIN PARTS OF A MONOLITHIC REGULATOR
• Reference voltage circuit
• Error Amplifier
• Series pass element