[AMPS] AL1500

[Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)]

Earlier, I wrote:

>So the way it's  normally meant to operate is that grid current flows 
>down through R3
[...]
>What happens to Q2 in a major surge depends on the other things 
>connected to R20. If the circuit is at all conventional, R20 is the 
>grid current metering resistor, so there must be a meter connected 
>across it, and hopefully also a protection diode (anode to ground). 
>Then the B-minus rail and anode current meter connect to the top of R3.
>
>R20 is in the path of any major current surge from B+ to ground, as it 
>flows up through R3 to return to B-minus. If the protection diode is 
>connected across R3, the voltage drop will not exceed say 0.7-0.8V, so 
>both R3 and Q2 should survive OK.

Sorry - "R3" should be R20, everywhere.

-- 
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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