variable capacitor

C

chikedef

New Member

• Nov 20, 2009

• #1

can l use a tuning capacitor on the radio receiver as a variable capacitor on my FM transmitter. wat is the range of the capacitor that is tha max and min capacitance

 

k7elp60

Active Member

• Nov 20, 2009

• #2

Yes you can. The tuning ratio of the the transmitter is generally the sq root of the capacitance ratio. The tunning ratio is the maximum capacitance/minum capacitance. If this ratio is 9:1 then the tuning ratio of the receiver will be close to 3:1.

 

Last edited: Nov 20, 2009

audioguru

Well-Known Member

Most Helpful Member

• Nov 20, 2009

• #3

stray capacitance of the wires on the pcb increase the minimum capacitance of a trimmer capacitor.

 

k7elp60

Active Member

• Nov 20, 2009

• #4

Audioguru is correct, one has to take ineffect the stray capacitance...especially at standard FM broadcast frequencies.