The first two feed grids that have a higher impedance than a diode that
is fed by the third.

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73
Hank WD5JFR
"Theo" wrote in message
...
In an old-style valve (tube) communications receiver circuit which
utilises two I.F. stages and uses three I.F. transformers, can someone
explain why the last I.F. transformer (which feeds the diode detector
stage) need to differ in some way to the other two?
Any help would be greatly appreciated.

Theo