[ARC5] Circuit Help Needed

[Kenneth G. Gordon]

On 11 Feb 2017 at 11:09, Richard Knoppow wrote:

>      However, this is NOT a cascode amplifier, its two triodes in 
> cascade.

Yes. Tom pointed that out to me, thanks.

> A cascode amp has the two tubes in series with the plate of the 
> first tube going to the cathode of the second. When made from two 
> triodes it has similar characteristics to a pentode but a cascode can 
> also be made with a triode and pentode in series where the pentode acts 
> as a constant current load for the triode. Cascode amps were commonly 
> used as low noise RF amplifiers in television receivers.

and were sometimes used in amateur VHF circuits.

In any case, the cascode is an interesting circuit.

Mark's power supply is the first such HV regulated variable supply I have ever seen which 
uses a cascade dual triode as the control device. To me, the circuit is overly complex, but 
as long as it works well, who cares? :-)

Ken W7EKB

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