Hi,
I'm trying to find a transistor or N FET but my electronic knowledges are very limited.
Anybody can you help me to find a correct transistor or N FET to complete the diagram below?
This will be used to turn on/off a GPS connected to a ESP32 using any GPIO pin.
This component(s) must consume less current as possible because the ESP32 is powered by battery.
Also this must "cut" the positive, not the negative.
Thanks!

 

Why can't you connect the GPS directly to the I/O pin. I believe they are rated at 40ma max.

 

Hi,
I'm trying to find a transistor or N FET but my electronic knowledges are very limited.
Anybody can you help me to find a correct transistor or N FET to complete the diagram below?
This will be used to turn on/off a GPS connected to a ESP32 using any GPIO pin.
This component(s) must consume less current as possible because the ESP32 is powered by battery.
Also this must "cut" the positive, not the negative.
Thanks!

View attachment 219083

Why do you think you need a FET or a transistor.

 

Does the GPS have a shutdown pin or a shutdown command?

 

Welcvome to AAC!

Also this must "cut" the positive, not the negative.

A P channel MOSFET or PNP transistor would work. There are many types of FETs. When I see FET, I think JFET and that isn't what you want.

 

Why can't you connect the GPS directly to the I/O pin. I believe they are rated at 40ma max.

I read it's not for constant drain. But maybe I can use 2 or 3 pins at the same time to feed the GPS? What do you think?

 

Does the GPS have a shutdown pin or a shutdown command?

Unfortunately no.

 

Welcvome to AAC!

A P channel MOSFET or PNP transistor would work. There are many types of FETs. When I see FET, I think JFET and that isn't what you want.

Thank you! I was looking for it, but can't decide which one. What parameters should I look for? How can I know which one will consume less power? Tks again

 

But maybe I can use 2 or 3 pins at the same time to feed the GPS? What do you think?

I was going to suggest that very same thing. Two pins should be sufficient.

 

What parameters should I look for? How can I know which one will consume less power?

When you use either as a switch, power dissipation is minimal.

If you use a MOSFET, you need a logic level device that will turn on hard with a Vgs of 3.3V. You don't have that problem with a PNP transistor, but the transistor will require more current from the I/O port. For transistors like 2N3906, you need to provide one tenth of the load current. For BC557, you only need 5% of the load current.

EDIT: You also need to consider maximum collector-emitter/source-drain voltage and current capacity, but 3.3V and 25mA won't require more than a general purpose device.

 

Why can't you connect the GPS directly to the I/O pin. I believe they are rated at 40ma max.

Initial current draw of the GPS will likely reset the uC. FET switch is the best way.

 

Initial current draw of the GPS will likely reset the uC. FET switch is the best way.

Possible but why not give it a try.

 

I will try to use multiple GPIO pins together first. Maybe I don't need any extra component. I let you know the test results. Thank you all very much!

 

I will try to use multiple GPIO pins together first.

You will obviously have to be absolutely certain that one output is never high while the other is low.

 

The multiple GPIO solution didn't worked.
The GPS is really draining 60mA.
I'm testing a IRLB3813 with source connected to the VBAT and looks great.
Thank you all for the help!