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LF: component replacements

To: [email protected]
Subject: LF: component replacements
From: "Dick" <[email protected]>
Date: Sat, 20 Mar 2004 19:42:17 +0100
References: <[email protected]> <000801c40ea5$67af4930$bb4036d2@mcalevey>
Reply-to: [email protected]
Sender: [email protected]
Hello all,

I'm not an expert in all the special types of components
around, so therefore some questions here.

In several transmitter designs I found a skottky diode MBR150
in the gates of the FET's.
As I don't have them here (yet?) I was wondering if these can be
replaced by other types of (schottky) diodes.

First question: the MBR150 is a 50V/1A type. Can I use types
with higher currents, and how important is the voltage rated?

Second question: as fas as I understand schottky diodes are extremly fast,
but what about the use of so called 'very fast soft-recovery
avalanche'diodes,
like the BYV26 or BYV 28 with Trr of 25ns?
I have plenty of them in my junkbox, but really no idea whether these are
fast and/or usable for this purpose.

Finally an question about David, G0MRF's 300W transmitter (actually should
ask it
David personally......) that one uses an H11L1 optocoupler with
schmitt-trigger output
in it's protection circuit.
Wonder if that one can be replaced by a normal transistor type output
optocoupler.

It is a bit frustrating to find some components so hard to find here in
Holland.......
Some designs seem to use several "exotic" components which make it rather
difficult to build them right away.......

73 Dick, pa4vhf



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