walid Posted September 8, 2005 Report Share Posted September 8, 2005 The varicap is a special diode that which changes its capacity according to DC voltage applied to it in reverse manner, that is when high DC => low capacitance and vice versa, I think this is OK.Now, looking to Fig.varicap (FROM: http://hem.passagen.se/communication/bug_rf.html), the varicap is BB149A, this varicap (according to its datasheets) has acapacitance of more than 20pF for DC votage less than 1VDC.Lets assume for a moment that its capacitance is 20pF. As seen in the Figure, this BB149A is connected to other capacitors,i.e. 3.9pF & 15pF and the three elements with L1 combine an LC circuit.My question is: What is the equivalent capacitance of the three mentiond above with explination about series or parallel.THANKS. Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted September 8, 2005 Report Share Posted September 8, 2005 I'm not going to tell you the answer but I'll tell you how to figure it out.Capacitors in series:Ctotal = 1 / (1/C1 + 1/C2+ 1/C3)Capacitors in parallel:Ctotal = C1 + C2 + C3If you need more help then don't be afraid to ask. Quote Link to comment Share on other sites More sharing options...
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