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[AMPS] Blown TL922A... What to do?

To: <amps@contesting.com>
Subject: [AMPS] Blown TL922A... What to do?
From: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Mon, 11 Sep 2000 17:25:33 +0100
measures wrote:
>
>>
>>measures wrote:
>>>The grid protection circuits I am talking about are those that provide no 
>>>protection because the transistor that interrupts has too low a current 
>>>rating and it shorts during a glitch -- thereby affording no protection.  
>>>
>>Failure of that transistor to survive a glitch/arc/parastic/flash-
>>over/whatever is a simple DC design fault that can be cured by a 10K
>>resistor. 
>>
>A 10k-ohm resistor can prevent C-E shorts due to excessive collector 
>current?
>
>>I don't think that's a good reason to remove grid current protection for
>>normal operation.
>
>Replacing a shorted transistor with a fuse-R is hardly removing 
>protection.  Shorted transistors afford no protection because they can 
>not turn off.  

We may be talking about different transistors. Let's start again.

Where in the circuit is the transistor that you say burns out in a
glitch?

Why do you believe that it should be removed, if that also involves
disabling grid current protection in normal operation?

73 from Ian G3SEK          Editor, 'The VHF/UHF DX Book'
                          'In Practice' columnist for RadCom (RSGB)
                           http://www.ifwtech.com/g3sek

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