[ARC5] Switching the dreaded B+ line.

[Bruce Long]

Leslie   With some time I CAN FIGURE OUT HOW TO YOU YOUR 900 V    ( sorry for the caps) n-fets  Can you send me a schematic of the BC-457 or a link so I can see exactly what the relay does?   thanks   bruce

PS Zuzu who is here at my desk working on her math homework  says hello and hopes your lizard family is doing well.


      From: Leslie Smith <vk2bcu at operamail.com>
 To: ARC-5 List <arc5 at mailman.qth.net> 
 Sent: Saturday, April 1, 2017 5:14 PM
 Subject: [ARC5] Switching the dreaded B+ line.
   

Good-day all,

I wish to build a control box to switch the B+ line to the PA and
oscillator circuits in the same way that the selection relay (I think
it's K-53 or relay 53) does.  (This is for a BC-457 - soon to become a
BC-696 ... or a pseudo BC-696 ... )  

But what if  relay K-53 has been "pilfered".  Hmmm?  What if I want to
have a control box with a 3 position switch,  "Spot, Receive, Transmit"?
  That would be a useful switch to have on a control box.  

I could, of course, use a relay, wired in the say way as K-53.

OR (this is such a clever idea I can hardly believe *I* thought of it
...)  I can use an enhancement P-Channel MOSFET in place of the relay.  
 I looked in all the usual places and found nothing over -600V and
nothing under $10.oo    Nothing?  Really?  Seems I didn't look very
hard.  Hmmm.  I have tubes full of 900V 5A N-Channel MOSFETS here, but
I've never had the need for a P-Channel device.

Any ideas?  Hmmm?


Les

PS.  I've given up looking too hard.  Last time I looked for something,
(it was the SCR-274 manual) I looked for about 2 1/2  hours.  Nothing.  
Grrrr!  Then I asked here, and bingo!  In less than 5 minues Jim McVey
gave me a link!!  (Less than 5 minutes!!!)    Miracle!  The very one I
wanted!!  

Now we all know Jim is a nice fellow, but why did he have to wait until
I asked?  Why couldn't he just tell me, before I wasted 2 hours?  Jim?  
Hmm?  (Life is very difficult, I think ...)

(Maybe I'll use a PNP pibolar HV transistor switch.  Except no-one makes
pibolar.  Oh, I get it!  I'll use bipolar. )
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