[Milsurplus] Transistors for the PRC-47 Power Supply.

Wed, 11 Sep 2002 06:05:50 +0400

Hi George,

The PRC-47 supply is set up to provide HVand filiments to the PA and driver
tube in a power oscillator type system.  No reason at all that power hexfets
couldn't be used, as they will also work in this configuration.  I think
that it's just that most of us never really think of them.  I have used some
of the power MOSfets for this type of work, and they run a lot cooler at
load.  I may have to cobble something together and see how it flys.  Nothing
like doing some "thinking out of the box" once in awhile.

Thanks,   John  WD5ENU/A45XV

----- Original Message -----
From: "aGEnuine ham" <[email protected]>
To: <[email protected]>
Cc: <[email protected]>
Sent: Tuesday, September 10, 2002 9:40 PM
Subject: Re: [Milsurplus] Transistors for the PRC-47 Power Supply.

> John and group:
>
> I presume this is a switching inverter type power supply.  If not, sorry
> for wasting the bandwidth.
>
> Inverter design involves a number of trade-offs, but the efficiency is
> tied directly and unalterably to the voltage drop across the switching
> device in the on state.  If you are going to the trouble to redesign,
> silicon bipolar devices will be less efficient than germanium because of
> the ~.6 v drop vs. the ~.4 for germanium.  Why not instead, use the more
> efficient hexfets as newer designs do?
>
> Switching regulators using hexfets are more efficient than their silicon
> and germanium counterparts also, but since these are typically in line
> operated power supplies, it usually isn't a consideration.
>
> 73,
> George
> W5VPQ
>
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