Real hardware does not lie....I need to do some testing with real hardware which has now arrived from Mouser.
?
73 Kees K5BCQ
---------- Original Message ----------
From: "Jerry Gaffke via Groups.Io" <jgaffke@...>
To:
[email protected]Subject: Re: [BITX20] #bitx40 #ubitx
Date: Wed, 28 Mar 2018 18:43:49 -0700
Page 3 of the Fairchild/OnSemi datasheet (page 4 in pdf reader), under Output Detector
says C4-6 is 15pf max, where pins 4 and 6 are source and drain of the output side optical FET they hide inside.
Could drive some other attenuator, we don't need to use the optical FET as the attenuator, if that's what you mean.
But at that point, I'm not sure why we don't just replace the H11F1M with a piece of wire.
Perhaps there's something special about the transfer characteristic?
On Wed, Mar 28, 2018 at 04:55 pm, Sandy T wrote:
I might add that the 15pF is due to the LED which does have to be driven by the audio section second amplifier (with a current limited maximum of about 30mA). The FET Output (attenuation) can be elsewhere.
