How to choose a correct transistor or N FET

Thread Starter

ticofortes

Joined Oct 8, 2020
6
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!

1602195244715.png
 

Papabravo

Joined Feb 24, 2006
14,661
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.
 

Thread Starter

ticofortes

Joined Oct 8, 2020
6
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
 

dl324

Joined Mar 30, 2015
11,846
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.
 
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Thread Starter

ticofortes

Joined Oct 8, 2020
6
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!
 

Thread Starter

ticofortes

Joined Oct 8, 2020
6
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!
 
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