thanks for the answer
how would the current in the circuit be calculated?
the way I see it, which could be wrong in parts, is
if F3db = 491 hz
a) Rt = R1//R2 = 690 ohms
b) XC = 1/(2PI*F*C) = 690 ohms
therefore
c) Z=SQRT(XCsqr + Rtsqr) = 976 ohms
d) I=V/Z = 5/976 = 5.1 mA
this isnt the same result I get in the simulator. How does the .6V drop across the diode affect the current? ie when V>.6v the diode conducts but surely the above calculations assume the diode is conducting all the time? or at least not in the circuit?
thanks