>Well, so far the only significant reason that has been offered, by Steve K,
>is that for fast transients, the rectifier string "appears to be a string of
>small capacitors." True enough, and indeed small they are. Down in the 10pf
>range.
>
True enough.
>Now. lets consider this in context. These rectifiers will typically appear
>on
>the secondary side of a large transformer that is not exactly a shining
>example of high-frequency transformer design. Although I have never gone
>looking for it, I would not expect to see much high frequency energy on the
>secondary side. Especially peaks in the range of many kilovolts.
>In order to get anywhere with this line of reasoning, we need to adopt a (or
>some) generic models of transient pulses and look at the possible results. I
>think it is futile, however, because of another practical factor. In a
>typical full-wave rectifier, one leg of the rectifier is always in
>conduction. This provides a path from the transformer, through the
>conducting rectifier (very low R) through the filter caps (low Z for all
except UHF
>transients) and back to the transformer. Hence, any high-voltage transient
>that would happen to make through to the secondary during the 'off' period
>of the other rectifier would likely be highly suppressed. I can't see how it
>could ever even develop any kind of energy-bearing waveform across our
>string of diodes/capacitors.
>
? It can't, Eric. Good logic, methinks. However, with half-wave
rectification, only the forward transient is stored in the filter
capacitor, so shunt capacitors across the diode string is needed for
reverse protection. So how many turkeys use half-wave rectification for
anode and/or screen supplies?
>The basic technical issue at work here is still hanging wide open, and I
>maintain my challenge to anyone to offer something we can chew on. That is,
>how do you get all the rectifiers in the string into simultaneous
>conduction?
? Use same-type diodes in series, and put nothing in parallel with 'em
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