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.
View attachment 37576
View attachment 37577
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.
View attachment 37576
View attachment 37577
