ESP8266 Community Forum

- Tue May 02, 2017 1:57 am #65466

Two are very stable and work without a reboot and without reset a simple counter program. The two have also no pullup or capacitors connected, power source PC USB. Still great.

Can you share the purchase place for the two that seem to be high quality?

- Sat May 06, 2017 6:36 pm #65664 Unfortunately, I do not know where I bought the good one. I have bought in the past months at Ebay China various other components and mostly additionally then one ESP12E. (Actually just because these were cheap and not because I needed them just now.) I put them in the drawer.

With my main ESP12E I have then built a prototype and when I wanted to make more of them, I noticed the problem with the stability with the others.

- Wed May 10, 2017 5:19 am #65796 One thing that could be wrong is that you have used a 470uF capacitor.

The capacitor is there for decoupling, i.e. for smoothing out the power to the ESP-12 very temporarily.

I assume you have used an electrolytic capacitor? The problem with these in this application is that the parasitic inductance is much higher than for ceramic capacitors which are usually used as decoupling capacitors. The parasitic inductance reduces the ability of the capacitor to smooth out quick variations in power consumption.

If this matters in practice is hard to tell. In some photos of an ESP-12 there seems to be a decoupling capacitor under the hood already, on other photos there is none. If your ESP already has decoupling inside the external decoupling should not matter so much. Some problems could also be caused by long leads to the components. These increase parasitic inductance.

You could try to replace your 470u capacitor with a ceramic one and try to keep the leads as short as possible to the VCC and GND pads on the ESP12.

I hope this helps in your debugging. This seems like a tricky problem to solve.