I have a "Filter Choke" as it is described in the schematic for a Plilco model 45 radio. It looks like a small upright transformer with two leads. The resistance across the leads shows no circuit. How would one go about determining the value as its not listed in the schematic.

: I have a "Filter Choke" as it is described in the schematic for a Plilco model 45 radio. It looks like a small upright transformer with two leads. The resistance across the leads shows no circuit. How would one go about determining the value as its not listed in the schematic.

Kevin

You can use a choke rated at 10 henries @ 65 ma. The exact value is not critical. Also replace the filter caps in the radio with 10 mfd 450 volt.

The choke acts as a high resistance to AC and low for DC. It's AC resistance is determined by the formula 2piFL. (6.28X120X10) = 7536 ohms to ripple from the full wave rectifier while the DC resistance would be closer to 200 ohms..

Norm