2 Wrote:
>>
>>Paul and I favor the TL431-TIP147 bias circuit because we supply our
>>different control boards for a large range of tubes, so we need a 'one
>>circuit fits all' solution. Maybe that makes us biased?
>>
>I am biased toward simple, minimal-cost, glitch-resistant circuits that
>work. The [Figure 7] optoisolator/10A, Si-npn switch/3A diode-string
>will reliably handle a 3cx3000A7 and it switches in under 7uS.
>
>>However, if you're also going to use EBS, the TL431-TIP147 circuit has
>>everything you need - the power transistor and the switching facility
>>too. To bias off the tube, simply switch the control gate of the TL431
>>to its anode (collector of TIP147). Switching time is a few
>>microseconds.
Both circuits can make equally valid claims of simplicity, low cost and
glitch resistance. They just get there in different ways.
--
73 from Ian G3SEK
www.ifwtech.co.uk/g3sek
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