If the notion that the rectifier's cathode is positive in relation to the rest of the radio, remember that the cathode in a tube is not negative itself EXCEPT in relation to the OTHER PARTS INSIDE THE TUBE. The cathode is SUPPLIED with negative energy, so that would make it positive in relation to the negative energy. The radio is negative with respect to the rectifier cathode. Make sense? Hope so. This one can confuse people. It makes perfect sense to me, but I've thought about it A LOT. It also helps to dump the idea that electricity flows from positive to negative. Electrons are negative, and they are what moves. Basically the rectifer allows current to flow one way (as does any other tube, but if the other tubes were used as valves instead of being supplied with filtered DC, this would interfere with their performance). It does not matter where the rectifier is placed in the circuit (beginning or end) as long as it is oriented in the right direction. Rectifier tubes in radios are almost always placed at the end of the negative current flow. I have yet to see a radio built otherwise. Current can only flow one way through the radio, so negative current flows in from the line cord (or transformer center tap in an AC radio) and goes to all the cathodes of the radio tubes. It goes through the radio tubes and then to the rectifier cathode. It then goes through the rectifer and back to either the power transformer or the line cord.
Thomas
:The positive side of electrolytics should always face the rectifier. The first one should be connected with the positive directly to the cathode of the rectifier, and the second goes with the positive to the field coil which goes to the cathode of the rectifier. Even when replacing an electrolytic in the cathode bias resistor section of the output tube, just remember this....trace through the tube, back through the output transformer, and on your way to the field coil and then to the rectifier.....that's the positive direction, so if you were to replace an electrolytic at the place mentioned above, the positive side of the new electrolytic would face the output tube's cathode, which faces circuits that lead to the rectifier.
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:If the notion that the rectifier's cathode is positive in relation to the rest of the radio, remember that the cathode in a tube is not negative itself EXCEPT in relation to the OTHER PARTS INSIDE THE TUBE. The cathode is SUPPLIED with negative energy, so that would make it positive in relation to the negative energy. The radio is negative with respect to the rectifier cathode. Make sense? Hope so. This one can confuse people. It makes perfect sense to me, but I've thought about it A LOT. It also helps to dump the idea that electricity flows from positive to negative. Electrons are negative, and they are what moves. Basically the rectifer allows current to flow one way (as does any other tube, but if the other tubes were used as valves instead of being supplied with filtered DC, this would interfere with their performance). It does not matter where the rectifier is placed in the circuit (beginning or end) as long as it is oriented in the right direction. Rectifier tubes in radios are almost always placed at the end of the negative current flow. I have yet to see a radio built otherwise. Current can only flow one way through the radio, so negative current flows in from the line cord (or transformer center tap in an AC radio) and goes to all the cathodes of the radio tubes. It goes through the radio tubes and then to the rectifier cathode. It then goes through the rectifer and back to either the power transformer or the line cord.
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:Thomas