Well, Actually my issue is that one but at another level i have a similar problem with the board's sensor terminals. Here is the design Screenshot from 2024-07-30 17-03-42.png Because GPIO 32 qnd 33 can be used for digital and analog inputs, i added the 2N7002 so i can connect sensors that are 5v or...

Hello, I read about the attenuation variable when using the ADC. I am just a bit confused. I know that the mac voltage you can apply to a pin is 3.3v, however it seems that there is not really a way to read a voltage higher than 2.45v ? i mean if i apply a voltage of 2.8 to a pin, does that mean tha...

Hello, Actually the original reason i started this thread is because i made a board where i connected the battery + directly to the ADC pin. The problem is that when the board was not energized the rtc battery would be drained in less than 2 days. So that is why i thought of a resistor or a divider....

Thanks for that info.
Just to confirm, I will use only a 2Mohm resistor between the positive of the battery and the GPIO pin. Then when the value of the ADC falls below 2.45V i will flag the battery as needing replacement. Is that correct?

thanks

Hello, The board i am designing has an rtc chip and a 1220 3v coin battery as bacup power. I want to monitor the battery voltage using anm ADC pin but i am worried about current leakage. I thought of either putting a voltage divider with 2Mohms and 1 Mohm as resistors and connect the pin there, the ...

Hello, i have a very similar problem. i have an rtc which uses a 1220 battery 3v as backup power. i want to read the voltage of the battery using an analog pin and to avoid draining the battery when the power is off i thought of connecting the output lf the battery to the pin on the esp32 with a vol...