Gaps in the collection (was Re: rarest computers. )

From: Dwight K. Elvey <>
Date: Tue Aug 17 16:43:19 2004

 Reading the article by Sir Douglas Hall, he mentions
making an adjustment to keep the positive feedback below
the point of oscillation. This sure sounds like regenerative
to me. Regenerative feedback was used quite often to
increase the effective Q of circuits to increase selectivity.
The article of May 1976 seems to indicate that this is how
this circuit works. This makes sense. There are many, many
ways to introduce regenerative feedback. One of the
early ones was to place a variable coil in the plate
circuit that was not coupled to the tuned input. The
circuit worked by the parasitic capacitance of the triodes
grid to plate. This can be done with a transistor as well.
 I remember when I was a kid, I had one of those 2 transistor
reflex receivers made by GE ( wish I still had it ). I
modified it to be regenerative and was able to greatly
extend both range and selectivity. At night, I pulled in
stations across the US.

>From: "John Honniball" <>
>Geoffrey Thomas wrote:
>> Yes, thanks - but the author had a special name for it - that's what I can't
>> remember.
>Was it "regenerative"? Or is that a different type of circuit
>altogether? See, for example:
>John Honniball
Received on Tue Aug 17 2004 - 16:43:19 BST

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