You could use a 74LVC245 tristate driver (I'm stuck with a bunch of them) or 74LCX07 hex buffer or 74LCX541 octal buffer that are 5V input tolerant and drive 3.3v outputs, but you would loose the analogous of the signal -- it would be conditioned to a digital signal.
For a recommended solution, look at Microchip's tipsheet: http://ww1.microchip.com/downloads/en/DeviceDoc/chapter%208.pdf, specifically solution #12 for a resistor divider, or for your circumstances an active transistor clamp like solution #11. On Fri, Jun 26, 2020 at 11:19 PM The MacDougals via TriEmbed < [email protected]> wrote: > My electric fence monitoring project is making progress. > > > > Attached is a scope shot of the signal I am trying to monitor. > > There are two issues I want to address before putting this signal on the > A0 pin of my ESP8266 development board (D1 mini). > > The spike to ~5 volts is concerning. I think I can use a 3.3v Zener diode > to suppress this. Installed between my signal and ground with the banded > end away from ground. > > The negative lobe of the signal is also concerning. Can I just use a > diode in series here? Banded end toward the A0 pin. I can adjust the > voltage up a bit to compensate > > for voltage drop across the diode. > > > > I have drawn up a schematic of what I think is the solution. > > > > Thanks for any comments. > > > > ---> Paul > > > > > _______________________________________________ > Triangle, NC Embedded Computing mailing list > > To post message: [email protected] > List info: http://mail.triembed.org/mailman/listinfo/triembed_triembed.org > TriEmbed web site: http://TriEmbed.org > To unsubscribe, click link and send a blank message: mailto: > [email protected]?subject=unsubscribe > > -- Scott G. Hall Raleigh, NC, USA [email protected] *Although kindness is rarely a job, no matter what you do it's always an option.*
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