by EWBrown » Mon Mar 10, 2008 1:02 pm
To estimate the impedance or inductive reactance of the choke, the formula is XL = 2*pi*F*L, with F in Hz and L in Henries.
For 120 Hz (the usual ripple frequency freq, right off the rectifier cathode,
6.28*120*L (henries)
Effectively Impedance would equal 754 ohms (xL) per Henry.
So, if you are using a 5 henry choke, with 200 ohms DCR, the
choke, in terms of a resistor, would look like 200 ohms to DC, but
3770 ohms impedance or inductive reactance to the 120Hz ripple.
HTH
/ed B in NH
Real Radios Glow in the Dark