https://www.digikey.com/product-detail/en/on-semiconductor/1N5223B/1N5223B-ND/977556
13 cents Wire it up backwards and it will have a constant 2.7 voltage drop across it. It is good for a half watt. So, as long as your current to the arduino stays below 185 milliwatts you will not smoke the zener. There are larger zeners available. From: Jason McKemie Sent: Wednesday, November 1, 2017 10:57 AM To: af@afmug.com Subject: Re: [AFMUG] OT: Electronics Question I was under the impression that the cap was for smoothing out the power to the Arduino (actually a nodemcu esp8266 module in this case). Apparently these things can act strangely without a good clean power source. On Wed, Nov 1, 2017 at 11:49 AM, <ch...@wbmfg.com> wrote: Your diode needs to be larger than the total current the combination will draw at peak. The cap could be for power supply filtering or emi or ? Not really sure. You could use just a 2.7 volt zener diode (reverse biased) inserted in series with the Arduino to knock off 2.7 volts off of the 6 volts. From: Jason McKemie Sent: Wednesday, November 1, 2017 10:27 AM To: af@afmug.com Subject: [AFMUG] OT: Electronics Question I'm rigging up an Arduino controlled blind setup and trying to configure the power supply. The installation will have an Arduino (3.3v) and a servo that will operate at around 6v. I was going to supply the whole thing with 6v and use a step-down converter on the Arduino. Someone recommended using a diode on the + input, and a cap across the inputs to the step down - how would I go about sizing these appropriately?
