ESP32 – Understanding DOIT ESP32 Devkit V1 Schematic

capacitoresp32

I'm creating my own small dev board for the esp32 wroom module.

I'm following the schematics for the DOIT devkit v1 module.

Power Schematic

Full schematic here: https://embedded-systems-design.github.io/overview-of-the-esp32-devkit-doit-v1/SchematicsforESP32.pdf

I'm unable to workout if I need a polarised capacitor or if I can use ceramic for all.

Given the schematics there is no plus (+) sign on the capacitors.

But on the dev board itself, I can't seem to find what the below highlighted capacitor is for.

Dev board pic top

Looking on ebay at 3.3v regulator modules, they all seem to come with ceramic only caps, so I can't say for sure if this is part of the power supply.

I'm guessing it is the 100nF C2 cap, but that is a guess and then if it is, do I need to use a Tantalum Capacitor or could go ceramic for all?

Best Answer

It should generally work. In fact, usually for power supply purposes, ceramic capacitors are slightly preferable to tantalum (your polarized cap looks like a tantalum type) capacitors, because they have lower internal series resistance.

Two caveats:

  • Ceramic capacitors, especially of the larger-capacitance types, have lower capacity at higher bias voltages. So, make sure your 10 µF capacitor is rated significantly higher than 3.3 V; going for anything less than 16 V rating probably is a bad idea
  • In some circumstances, the higher resistance is a feature (not a problem), because it can dampen control loops and limit oscillations. That's probably not the case here.
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