My brain got got a little ahead of my fingers.
That should be _without_ extinguishing the diode...
Oops...
On May 22, 2006, at 6:47 PM, Jack Brindle wrote:
Interesting solution. Be aware that neon lamps fire at about 60-70
volts. At that voltage you have _definitely_ exceeded the PRV of a
1N4148! You might want to consider a heavier diode in this
application - the 1N4007 should take quite a bit higher PRV,
allowing the neon lamp to illuminate with extinguishing the diode.
On May 22, 2006, at 6:25 PM, Mike Scott wrote:
Now, that solution shows the power of the group!
All this piker could do was look up a 200V diode or suggest
connecting two
in series.
When the NE-51 lights you know you have exceeded the diode reverse
voltage!
And it's time to add a resistance pad.
Mike Scott
AE6WA
Tarzana, CA
Elecraft KX1
40M Inverted V
20M Dipole
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Al Gulseth
Sent: Monday, May 22, 2006 5:44 PM
To: elecraft@mailman.qth.net; [EMAIL PROTECTED]
Subject: Re: [Elecraft] Elecraft RF Probe
Funny you should mention that -- just in the past few days I was
browsing
through an old [1968 edition] ARRL "Hints and Kinks". In an
article titled
"Diode Protection for the Heath R.F. Probe" the author suggested
adding a
NE-51 neon lamp across the diode (a solution he came up with after
frying
"three or four" 1N34s). This should work for the Elecraft probe as
the
schematic shown in H&K for the Heath probe is virtually identical
to the
schematic in the K1 manual (the only difference is a .005 vs. .01
cap for
the
input coupling and the polarity of the diode).
73 es GL, Al
On Mon May 22 2006 06:53 pm, [EMAIL PROTECTED] wrote:
Date: Mon, 22 May 2006 17:22:23 -0500
From: "Stan Rife" <[EMAIL PROTECTED]>
Subject: [Elecraft] Elecraft RF Probe
To: <elecraft@mailman.qth.net>
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset="US-ASCII"
I forgot to mention that I put a 1N4148 in and it seems
to have
taken it out too.
I put too much voltage on my poor probe. Is there a
heavier diode
that will take a little more voltage, say around 70v, that I can
replace
the 1N31A with?
Stan Rife
W5EWA
Houston, TX
K2 S/N 4216
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