Re: Terry's DRSSTC - All Ready!!

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Gerry,

At 10mA (twice what I need) I measure the forward drop of the 1N5819 at 
only 0.26 volts.  So I have 40mV to spare ;-))  The level does not need to 
be exact at all and as long at it works reliably.  I am also running out of 
room on the card these days too.  But using the Schottky diodes seems to 
fix the LM339 up fine!  Zero problems with the circuit now!!

Cheers,

        Terry


At 11:55 PM 3/3/2005, you wrote:
> Hi Terry,
>
> If you tie the anode side of D3 and D4 to a +0.6V reference (made with 
> another matching diode and resister), you can clamp at precisely 0V.
>
> Gerry R.
>
> > Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
> >
> > Hi Steve,
> >
> > > I also took on board (literally- I'm laying out a PCB) what Terry said about
> > > putting the burden resistor back on the driver board and transferring the CT
> > > signal as a current. I think I'll include that as an option on the board.
> >
> > Here is how my newest one looks:
> >
> > http://drsstc.com/~terrell/pcbart/ProtectionCard-02.gif
> >
> > http://drsstc.com/~terrell/schematics/Protection-1.1.gif
> >
> > I do all the heavy current stuff for the CT in the lower right...