Amateur Extra › E5 Electrical Principles › E5C10
E5C10
Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 400-ohm resistor and a 38-picofarad capacitor at 14 MHz?
Pick an answer to check it.
Answer: B. Point 4
XC = 1 / (2 pi f C) = 1 / (2 x 3.1416 x 14e6 x 38e-12) = about 300 ohms. The impedance is 400 - j300, which is 400 to the right and 300 down: Point 4.
Tip: Capacitive points plot below the axis.