[sdiy] JFET switch question

[Ian Fritz]

At 09:43 AM 4/27/2008, Tim Stinchcombe wrote:
>- however, with the diode reverse-biased for the switch to be ON, there is
>now no path for a current to remove the charge in the reverse-biased channel
>junction, which is needed to allow the JFET to actually turn on. The cap is
>necessary to supply this path, the implication being that the JFET might not
>actually switch on without it.

That's exactly what I was trying to explain before. Guess I didn't say it 
very well.  You can't just leave the gate open-circuit because its 
potential is indeterminate.  It needs to be tied to something that will 
bias the device into conduction.

   Ian