May I replace BAT85 with 1N5822 diode?

[jcgalvezv]

In my hometown I could not find BAT85 schottky (30V, 0.2A) diode but 1N5822 (30V, 3A). I would like to know if I can use 1N5822 as a replacement in my Enhanced Serial Download Circuit (picaxe_manual1.pdf page 32).

 

[manuka]

Try it & see, although it'll be an overkill at such ratings,which look more PV solar panel suited, & I suspect the switch on voltage may be rather too high for the job. Compare specs. yourself?

I guess you appreciate that almost any Schottky diode should do here, as only tiny currents (a few mA) are flowing & it's the low forward voltage drop rating ( ~.1 -.3V) that's being utilized. Normal Si diodes are ~0.6-0.7V of course. Other Schottky attributes, such as high speed & low junction capacitance, are pretty academic in this PICAXE enhancement context.

 

[hippy]

As the diode is there to clamp negative voltages an alternative is to use a blocking diode in series with the received signals. I've had no problems with this but haven't done comprehensive testing to check it works as well as the BAT85 solution. I suspect that it does ...

                 |\ |          ___
TX from PC >-----| >|-----.---|___|---- Serial In
                 |/ |    .|.
                         | |
                         |_|
                         _|_

 

[jcgalvezv]

Thank you manuka and hippy for your replies. I will initially try just replacing BAT85 with 1N5822 and if it doesn't work I will try with a diode in series.