[Elecraft] 1N4007 diode question?

Mon Apr 7 20:36:00 2003

Hi All

Ok I must amend my statement on the 1n4007. My curiosity got me to thinking
so an experiment was in order. I went out and bread boarded a circuit. It
looks like the entire family of 1n4000 exhibit the PIN characteristics. I
tried the 1n4001, 1n4002 and 1n4007 at different frequencies from 3 to 40
mHz at 5 volts Pk to Pk and they all work the same with a switching current
of about 8 ma. Just for grins I tried a 1n4148 and it does not work at all.
It rectifies the RF as you would expect. The 1n4007 passes the RF without
distorting it at all.

There are several articles on the web that mention that the 1n4007 is the
only one in the series that will work as a PIN diode but my tests seem to
discount that. So will a 1n4005 diode work in place of the 1n4007 in the K2
possibly, but I would still go back and use the proper part if possible.

Don Brown
KD5NDB

----- Original Message -----
From: "Don Brown" <[email protected]>
To: <[email protected]>
Sent: Monday, April 07, 2003 5:11 PM
Subject: Re: [Elecraft] 1N4007 diode question?

> Hi
>
> Pin diodes act more like variable resistors than diodes at RF frequencies.
> So think of D2, D3 and D4 in series when turned on and open circuits when
> turned off. If you replaced one of the diodes with a non PIN type (1n4005)
> then the other diodes may still provide enough isolation when in receive
but
> I would still replace the diode with the correct type (1n4007) that has
the
> PIN internal construction. Wayne may want to explain this more fully as I
am
> not an expert on this and I am getting my information from several
internet
> sites and the ARRL Handbook.
>
> Don Brown
> KD5NDB
>
>
> ----- Original Message -----
> From: <[email protected]>
> To: <[email protected]>
> Sent: Monday, April 07, 2003 4:01 PM
> Subject: Re: [Elecraft] 1N4007 diode question?
>
>
> > I've been reading with interest the comments about substituting a 1N4007
> > with a 1N4005.  When I built my K2 I quickly needed a 1N4007 (I now
> > forget the reason) and got a 1N4005 from the local RS store.  I
installed
> > it and it's still there.
> >
> > As I recall, the location was on the rear of the RF board (in D2, D3, or
> > D4).  After many hours of operation, I haven't noticed any problems in
> > T-R switching that might be due to this substitution.
> >
> > 73, de Earl, K6SE
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