[Test-Equipment] Transistor Circuit Design Question

[Barry]

I had not thought of doing that.  I had it in my head that power for the chip as well as the logic states needed to be positive with respect to ground but that's not the case.  While I may still need to invert the strobe signal, shifting the voltage levels up that way should not be necessary (and will eliminate the need for a separate +5v supply.

Thanks!
Barry - N4BUQ

----- Original Message -----
> From: "David DiGiacomo" <david at davmar.org>
> Cc: "Test Equipment" <test-equipment at mailman.qth.net>
> Sent: Monday, May 25, 2015 10:54:00 PM
> Subject: Re: [Test-Equipment] Transistor Circuit Design Question
> 
> On Mon, May 25, 2015 at 6:33 PM, Barry <n4buq at knology.net> wrote:
> > I have a situation where I have strobe and data signals originating from a
> > 3870 CMOS microprocessor (part of a Fluke 8050A) that I need to convert to
> > make them compatible with the display/latch I'm using to retrofit a
> > different display.
> >
> > The strobe is currently a positive-going pulse from -5V to 0V (GND).  I
> > wish to make this a negative-going pulse from +5V to 0V (GND).
> 
> 1. The 3870 is NMOS, not CMOS.
> 
> 2. Why don't you connect your new display between -5V and ground also?
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