Vext residual voltage when it's turned Off

Hello. I have the following problem. It’s being hard to use the Vext control. In my case, I’ve tested in two different devices (heltec esp32 LoRa V2) and I got same results. When Vext is On I get 3.3v aproximadetely. When Vext Off, I get 2.4v. I can’t measure 0v from the Vext pin.

The question is that I’m trying to use Vext for a buzzer, but it’s never turns off, cause always there is tension in this Vext pin.

Sorry about my english, hope someone can help me!

Try this setting.

I didn’t understand your suggestion. I’m trying do supply a buzze as an output. I just want to turn on and off the buzzer troughout the Vext 3v3 pin.

Hello, I have absolutely same problem. When I initialize the board like:

Heltec.begin(false, true, true, true, 868E6);
it works as expected (0 V on the Vext pin when Vext off),

but when I initialize like:
Heltec.begin(true, true, true, true, 868E6);
it doesn’t work properly -> (2.4 V on the Vext pin when Vext off).

So the problem is probably caused by OLED / I2C bus.

Does anyone now how to solve this? Thanks

Try with a 1kOhm Pull Down resistor, so the Vext pin can establish the Voltage on that resistance. I was having the same trouble.
I’m using Vext to energize some sensors but when I turned OFF the Vext pin it was still in 2.4[V], but with a 1kOhm resistor working as a pull-down resistance the voltage drops to 0,06[V].

I am having the same problem. Vext is not working. Running this sketch on two different Lora 32 v.2.1:

I get the following results:

Heltec.VextON(); Shows 2.45V
Heltec.VextOFF(); Shows 3.30V

A pull-down resistor did not help.

Try this setting.

Adding those two lines did not achieve anything.

I am still seeing between 2.4V and 2.8V when it should be 0.0V.

Does anyone have a solution that makes VEXT work as it is supposed to?

In your code, did you use 21,22 as IIC pins?

21 is not used except for VEXT.
22 is not used.