When I connect my ESP-01S to a breadboard power supply (3.3V), the built-in LED glows dimly. But when I use a USB programmer to connect it to my computer, the built-in LED glows brightly. Can anyone explain why this is happening and what I can do to fix it?
This is it connected to PC
This is it connected to breadboard power supply (3.3V)
(same as this one https://www.amazon.com/JBtek-Breadboard-Supply-Arduino-Solderless/dp/B010UJFVTU)
These supplies are very limited in there current (wattage) capabilities.
Use a power supply like these:
And what's going into that?
You need 7.5 ─ 8V into the barrel jack (or bust).
Well, according to that listing, the breadboard power supply board is nominally rated for 700mA max and has two outputs, each supplied by one of the AMS1117 regulators. I guess the manufacturer supposed 350mA per regulator, which might seem a reasonable limit since despite each AMS1117 regulator being rated for 1A, neither has a heatsink. Its ability to dissipate power in the form of heat is therefore severely limited.
However, checking the datasheet for the AMS1117, it states that without a heatsink or sufficient copper around it on the PCB, the ability of the regulator to dissipate power is limited to "less than 1W". The higher the input voltage, the more heat it has to dissipate.
(Vin - Vout) * current = dissipated power (as heat) in watts.
I agree that it would be helpful to know what this breadboard supply board is itself being supplied with?
(Post corrected following a couple of errors being brought to my attention)
Its connected using "coaxial power connector to USB" and USB part to my PC
Do you have a multimeter?
Have you tried measuring the voltage at the output of the breadboard power supply both with and without the ESP01 connected?
FYI you can use any amperage supply, the circuit will only pull what it needs, it will not just always pull the full amperage.
The amperage listed on the adapter (wall wart) is the MAX provided.
Which pin is the Built in LED on ? The units i have are on GPIO1 which is the TX pin.
Chances are the connections on the programmer use a voltage converter of some kind, possibly pulling the Pin LOW (or if it's on GPIO 0 then it is of course pulled down regardless.)
You won't know until you upload a simple sketch. (you haven't posted any code, so i figure this is just a simple test)
I am pretty sure this is not a power issue. The Led is the least power sensitive part of the ESP, it won't run when there is not enough current supplied, and it only needs 100mA to do that, but during WiFi connection there may be peaks up 300mA.
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