Research Article Open Access Volume 3 • Issue 3 • 1000132 J Electr Electron Syst ISSN: 2332-0796 JEES an open access journal Open Access Research Article Rana, J Electr Electron Syst 2014, 3:3 DOI: 10.4172/2332-0796.1000132 Keywords: Feedback; LC combination; Multisim; Tank circuit; VFO; Resonance; Magnetic energy leakage; Microfarad(uF); Oscillators; Sinusoidal Introduction Back in mid-1912, Edwin Armstrong while carrying out experiments with triodes wasn’t aware of a spectacular phenomena due to a component which was going to serve as the basis of coupling and amplifcation amongst many other applications. Until then, the experiments had incorporated these devices as a detector for amplitude modulated waves. Having utilized them for this functionality, nobody was aware of the reasons as to why that was happening. By means of coupling one terminal of the device to another, it was observed that he could achieve large signal gain. We today term the phenomenon as positive feedback in circuits. He, with his invention of the radio had produced a unique oscillator. Te uniqueness was justifed since the limitation of other oscillators producing output in the kHz domain had now been extended to the MHz domain [1]. Ever since then, there has been a plethora of oscillator circuits that have been invented and employed industrially worldwide. Continuous Sine Wave oscillators or Square wave oscillators fnd their application in a myriad of felds in converting DC input to a variant A.C. output, in amplifcation of signals, synchronization purposes to name a few. One such circuit which utilizes storage and dissipation of magnetic energy, namely the Colpitts Oscillator has formed the basis of this study. A few of modifcations in the conventional circuit have hereby been inferred. Te Colpitts Oscillator Classifcation Te Colpitts Oscillator is known to work on feedback from the divider setup that is used in the circuit. Te voltage divider is either made by 2 inductors or by using tapping on the single inductor. In either of the cases, if the desired application is that of a VFO, the usage is not as much preferred as with the case of Clapp Oscillator. In the latter, an extra capacitor is used for tuning to the optimum frequency and hence a better sustained waveform is achievable readily [2,3]. However, Colpitts form the basis of either of these circuitries, capacitor-tuned Clapp or the conventional circuit. And consequently, is believed in this experimental study to be encompassing the behavioral results for the counterpart circuits as well [2]. Frequency tuning and parameters that efect it Since the Colpitts oscillator is a type of tank circuit (LC *Corresponding author: Ankit Rana, B. Tech. (ECE), Bharati Vidyapeeth’s College of Engineering, A-4, Paschim Vihar, New Delhi-110063, India, E-mail: ankitrana1709@gmail.com Received September 01, 2014; Accepted September 19, 2014; Published October 01, 2014 Citation: Rana A (2014) Colpitts Oscillator: Design and Performance Optimization. J Electr Electron Syst 3: 132. doi:10.4172/2332-0796.1000132 Copyright: © 2014 Rana A. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Colpitts Oscillator: Design and Performance Optimization Ankit Rana* B. Tech. (ECE), Bharati Vidyapeeth’s College of Engineering, A-4, Paschim Vihar, New Delhi, India combination) and works on feedback of energy, the mathematical expression underlying its operation is the same as that of frst-order LC circuit i.e. ) * 2 / 1 ( C L f π = (1) And since, the Colpitts must have two capacitors for compensating purposes, the mathematical expression to obtain the frequency of operation is depicted as [4,5]: ) 2 1 ( ) 2 * 1 ( 2 / 1 C C C C L f + = π (2) It can be noted that the two capacitors in series with each other result in the expression in the denominator. From the study of its parasitic elements and the transconductance (g m ) concept, it is known that a negative value of input resistance only would be able to sustain oscillations at the output [6,7]. Oscillations are obtained only for a large value of transconductance (g m ) and for smaller values of capacitor elements used. Experimental Approach to Colpitts Oscillator Design A industrially acclaimed simulator, namely Multisim was used to observe the infuence of several parameters on a Colpitts oscillator design with multiple modifcations and optimization aims in mind [5,7]. A frst order Colpitts Oscillator has been drawn as a schematic over the simulator. Tis schematic circuit was introduced with several modifcations viz. change in input resistance, changes in capacitors and the inductor coil’s inductance. Te parameters mentioned herewith are the fundamental governing dependencies in the performance of a Colpitts Oscillator. Increase in the value of any of these would leave Abstract From the very fundamental oscillator, a simple pendulum wherein there is a constant energy switch between potential and kinetic energy, oscillators have seen groundbreaking changes in setup, operation and their applicability. There are harmonic oscillators which produce a continuous sine wave output of certain frequencies as per the passive components involved. Additionally, are known Relaxation oscillator which yield triangular, square and sawtooth waves as output to name a few. The present paper deals with the details of how a fundamental Colpitts oscillatory circuit can be designed. Furthermore, we would take a look at optimizing its performance with change in several dependent characteristics in oscillation. We would conclude with an inference pertaining to the best customization with could be put to practical usage. Journal of Electrical & Electronic Systems J o u r n a l o f E l e c t r i ca l & E l e c t r o n i c S y s te m s ISSN: 2332-0796