[Milsurplus] FET regulator

[MICHAEL ST ANGELO]

The newer high speed FETS have lower input capacitance that their predecessors. If it is a single band tramsmitter you can use a matching circuit for the input. It would be tough for a broadband amp.

I kinda remember an article in Electronics Illustrated using rectified and filtered line voltage without a transfomrer. It didn't put out much power because of the limited dissipation of the transistors.

Mike N2MS

 


> On April 7, 2017 at 5:10 PM Hubert Miller <Kargo_cult at msn.com> wrote:
> 
> 
> Understood. I think those use a  low impedance drive circuit. What i am asking about is the practicality of a single power FET transmitter, using one of the
> HF FETs so for example, it could use a B+ around line voltage. 
> 
> -----Original Message-----
> From: MICHAEL ST ANGELO [mailto:mstangelo at comcast.net] 
> Sent: Friday, April 7, 2017 2:03 PM
> To: Hubert Miller <Kargo_cult at msn.com>; milsurplus at mailman.qth.net
> Subject: Re: [Milsurplus] FET regulator
> 
> They have been using inexpensive FETSs for HF amplifiers for years. There are lots of 24-28 volt designs based on the IRF-510 that output 40 watt puch-pull.
> 
> Mike N2MS
> 
> 
> > On April 7, 2017 at 4:43 PM Hubert Miller <Kargo_cult at msn.com> wrote:
> > 
> > 
> > Could such HV FETs be used in a simple transmitter, similar to the one-tube transmitters of the past?
> > I mean, allowing for a good safety ratio to B+ and allowing for high SWR.
> > 
> > I recall an 'Electronics Illustrated' article from 1960 something that 
> > showed a transistor transmitter which was an analog of the single tube 
> > novice transmitters such as the Ameco AC-1 and such. It used two HV 
> > transistors in parallel at 175 volts for an input of 17 watts. It occurred to me that maybe these HV FETs have input capacitance that makes them impractical for this use.
> > -H
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