I forgot to write my question. quite soooory about it.
my question is

1. my ESP32-CAM board sometime runs OK but many times does not work well.
2. according to the e-book I checked one by one however could not find the answer till I found the voltage variation
3. when the power supply voltage is less than 4.85 volts the board does not work well, but the voltage is over 5.0V he is OK
4. I check the ESP32CAM specification sheet to find out the voltage tolelance but they just say *5V* with out plus minus
5. finally I found that the voltage should be over 5V otherwise he does not listen to me.
6. my question is …… the voltage specification is such critical ? …….  should be between 4.9V and 5.1V?

if anybody had the same experience, please teach me your experiences.
Thank you for your support
 
Jun Murata
 

Hi,
I have played with a few ESP32-CAM boards and found  it’s quite unstable,  traced the problem and found it’s mostly power related. I am using it on breadboard yet and made shortest power lines and added a few capacitors. It become more stable, but still not ideal.  I have not checked how supply voltage is critical for it, but will do some tests.
All the best, Konstantin

Hello Kon;
 
First of all I would like to show my great appreciations to you. You gave me the information really solved my big problems. Since I am making the adjustable voltage supply, I will check how the voltage affect hte ESP32CAM then report to you.
with my best regards.
Jun Murata
 

If you check the circuit diagram of the ESP32-CAM you will see it uses a AMS1117 voltage regulator. Checking the specifications of the AMS1117 shows that it requires a minimum of 4.8V to achieve the 3.3V needed for the ESP32.
 
Depending on the age of the IC this can change over time so could now be 4.9V or 4.7V (There’s no real way to know).

Hello Steve;
 
This time I got 2 responses, one is from Kon the other is from you. both information are quite usefull to me since I am just started with ESP32CAM module and would like to understand this module as deep as possible. Again thaks to both of you.
 
Jun Murata
 

Hello , Friends 
I am learner of ESP32, i want gratefull for all your sugestions and information about this issue, base on your information i use a DC POWER SUPPLY!, i could discover how much volts need each module o card in order work on! , i have an yihua 3005D,  grettings from SouthAmerica Ecuador!
pd. After that i apply a battery along AMS1117-3.3V.
 

Great!
Thanks for sharing your experience.
Regards,
Sara