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dscrobe 30th June 2008 07:33 PM

Full Wave Rectifier
 
On page 17 of the RCA, Receiving Tube Manual, RC-30, Copyright 1975, there is a basic schematic of a full wave rectifier. I am stuck on something here. With the way it is drawn, there are two winding on the secondary side of the transformer, the plate winding and the filament winding. Well, it appears that one side of the plate winding happens to be at the same voltage potential as the one side of the filament winding. If the case, how can the tube conduct?

lochness 30th June 2008 07:53 PM

I'm having a hard time visualizing what you're saying. Can you post a picture or drawing of it?

eds65gto 30th June 2008 09:09 PM

Full Wave rectifier
 
Hi:
In looking at the diagram in the RCA Manual the filament is not connected to the plate winding. I do not understand when you say the windings are at the same voltage potential. These windings are seperate and independent of each other.
The two plates of the rectifier tube are connected to the ends of the high voltage winding. The filament is connected to a seperate winding. The voltage output is taken from the cathode of the tube , for the positive and the center tap of the high voltage winding for the negative side. This is labled output to filter in the diagram.
Where did you get the idea the filament was connected to the plate winding?
Read the explanation on pg 17 for how this circuit works and you will get a better idea of what is going on.
Hope this helps
Ed

Miles Prower 30th June 2008 10:00 PM

Re: Full Wave Rectifier
 
Quote:

Originally posted by dscrobe
On page 17 of the RCA, Receiving Tube Manual, RC-30, Copyright 1975, there is a basic schematic of a full wave rectifier. I am stuck on something here. With the way it is drawn, there are two winding on the secondary side of the transformer, the plate winding and the filament winding. Well, it appears that one side of the plate winding happens to be at the same voltage potential as the one side of the filament winding. If the case, how can the tube conduct?
Part of the problem is that they show a rather uncommon indirectly heated dual diode there, not the more usual directly heated 5U4s or 5Y3s, and that the schemo uses the archaic style of drawing jump-overs. The two secondaries aren't connected, and the positive DC is taken directly off the common cathode.

dscrobe 1st July 2008 11:35 AM

Ed,
When I look at the two secondary windings, I am looking at them as if they were one complete winding, however, with a break in between. You could get a voltage reading across the whole imaginary winding. The filament winding would be 6.3 VAC and the plate winding would be about 280VAC. You would add 6.3 VAC to 280VAC to get the sum voltage across both windings of 286.3 VAC, for example. The part where there is a break, I am thinking if you were to take a voltmeter here, you wouldn't read anything. In other words, if I was to take a voltmeter and measure potential from the end of the plate winding (the end that is next to the end of the filament winding) and the end of the filament winding (vice versa), I don't think I would measure anything. That is where I am stuck on learning this.
Dan

dscrobe 1st July 2008 11:44 AM

Crap, I see the error of my ways here. The output is coming off the cathode. I thought I was seeing the output coming off the heater winding. Need to read schematics a little better. Thanks for feedback.

eds65gto 1st July 2008 07:35 PM

Hi:
Glad to help.
Ed


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