Diode Replacement

[Bob Burns]

In a message dated 01/03/2009 16:11:42 GMT Standard Time,  
davegoncalves at GMAIL.COM writes:

Hello,

For the HW-101, what would be a good replacement for the  1N191 - perhaps
the 1N4148?
It's used for an RF switch and simple  rectifier. Just to note - this is not
used in the balanced modulator.
--  
David Goncalves
W1EUJ



Hi David
 
The 1N191 is a gold bonded germanium diode with a PIV rating of 90V. If you  
substitute it with a 1N4148 in a signal detector you may get more distortion 
at  low signal levels as the forward conduction threshold of the 1N4148 is 
about  700mV whereas the gold bonded germanium diode is significantly less. If the 
 diode is used in a product detector where it is switched on by the BFO then 
you  probably will not notice any difference. 
 
In an AM detector at signal levels of several volts or more there may  not be 
any noticeable difference.
 
The AA117 is a gold bonded diode with a PIV rating of 90V so should be fine  
as an equivalent of the 1N191. The OA47 is gold bonded but only has a PIV 
rating  of 25V.
 
Hope that helps. Google 1N191 for more information.
 
73

Bob 

G3OOU
G-QRP  6907
_www.g3oou.co.uk_ (http://www.g3oou.co.uk/) 

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