David
glad to have been of help
At least there now seem to be adequate choices for solving the 'where have all the 2n2207's gone'
so thank you for your time and success in sorting out this issue
Christopher
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On 05/03/2018 18:33, Dave Wise wrote:
Thank you, Chris, for your kind gift of a Siemens?AF118 transistor for testing.
At least in the Q373?position*, your sample AF118 performed like a 2N2207.? I saw 60ns delay and 25ns rise vs 50ns/35ns for 2N2207, giving the same turn-on time.
That said, my recommendation stands: BC556 or KSA992, with 220pF added to the speedup cap.? That's cheap and abundant and anyone can do it, not just the oddball with a box of AF118's. ?:)
Thanks,
David
* Should be the same in the Q173 position but I didn't test it.
________________________________________
From: TekScopes@... on behalf of Christopher Hilton-Johnson chj@... [TekScopes] <TekScopes@...>
Sent: Saturday, November 25, 2017 2:15 AM
To: TekScopes@...
Subject: Re: [TekScopes] Re: Tek 547 A Sweep display during retrace
Have you looked at the AF118 as a replacement for the 2N2207?
I ask, because most of my pulls were AFs pretending to be 2Ns
Chris HJ?
