walid Posted April 21, 2012 Report Share Posted April 21, 2012 HiI noticed in many books that LC tank is connected to the base of the transistor, while connected to the collector in a real designs. Why this confusion?thanks Quote Link to comment Share on other sites More sharing options...
Hero999 Posted April 21, 2012 Report Share Posted April 21, 2012 You forgot the schematic. Quote Link to comment Share on other sites More sharing options...
Kevin Weddle Posted April 26, 2012 Report Share Posted April 26, 2012 Walid, A parallel LC filter circuit has a roll-off of 40db/decade outside the resonant frequency. An oscillator requires high gain, but it's selectivity can be independant of the gain circuit. The final design depends on the characteristics of the circuits and the components used. Quote Link to comment Share on other sites More sharing options...
walid Posted April 26, 2012 Author Report Share Posted April 26, 2012 Hi KevinIV,Have you ever design an oscillator?if yes, please tell me how with the related maththanks Quote Link to comment Share on other sites More sharing options...
Hero999 Posted April 26, 2012 Report Share Posted April 26, 2012 How can he provide such an in-depth answer without the schematic? That's impressive. ::)What sort of LC oscillator are you talking about?There are many configurations. The only thing you hint at, is you're using a BJT.Here are some examples:http://www.sentex.ca/~mec1995/tutorial/xtor/xtor7/xtor7.htmlIn all circuits, the base is connected to the LC tank in some way, perhaps that should give you a clue.If you want a decent answer, post the schematic. Quote Link to comment Share on other sites More sharing options...
Kevin Weddle Posted May 2, 2012 Report Share Posted May 2, 2012 Another aspect with these oscillators is the series capacitor inductor in parallel with the inductor. Not being a parallel LC means that the resonant frequency is not 1/(2pi x sqrt LC). The capacitive reactance does not equal the inductive reactance as it does in a resonant parallel LC. However, the reactance of the inductors will be equal at any frequency with a center-tapped transformer. Quote Link to comment Share on other sites More sharing options...
Guest remonx6 Posted August 2, 2013 Report Share Posted August 2, 2013 May i know about LC. is it Liquid Cristal ? ThanksAuthor Quote Link to comment Share on other sites More sharing options...
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