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Topic: Mosfet n channel issue with ESP8266 (Read 11890 times) previous topic - next topic

be80be

Those triangle things mean ground

flabombarda

Those triangle things mean ground
Thanks I will review the circuit based on this !

be80be

#32
Jun 02, 2016, 04:10 am Last Edit: Jun 02, 2016, 04:13 am by be80be
These are what are used as ground
 
The 3 too the right are used to show a ground the most.

Grumpy_Mike

Yes that triangle is the symbol for GND. All wires to that and similar symbols go to the same place even though wires are not shown.

ksartor

I'm actually trying to figure out how to implement this:


I have the components but I'm struggling to understand the schematic, especially what are the pins that go out from 2n3904 to p channel mosfet.

Thanks,

Hi could we have the p channel mosfet component reference?
Thanks you

flabombarda

#35
Jun 02, 2016, 05:32 pm Last Edit: Jun 02, 2016, 07:22 pm by flabombarda Reason: fixing diagram
Thank you all for the help !

Could you please validate the attached breadboard to see if it is correct based on the proposed schematic ?


thanks !

flabombarda

Hi could we have the p channel mosfet component reference?
Thanks you
I'm using this: 6nc60 as mosfet transistor.

Thanks

Grumpy_Mike

Quote
I'm using this: 6nc60 as mosfet transistor.
Sadly I don't think that will work. It is not a logic level FET, it requires 10V to fully turn it on, you only have 3V3.
Don't be fooled by the gate threshold voltage in the data sheet, that is just the point where the FET begins to conduct.

flabombarda

Sadly I don't think that will work. It is not a logic level FET, it requires 10V to fully turn it on, you only have 3V3.
Don't be fooled by the gate threshold voltage in the data sheet, that is just the point where the FET begins to conduct.
Correct Mike , not working :)
What would you recommend here ?

I'm considering the usage of a solid state relay if I can't make it work. Any thoughts ?

Thanks !

TomGeorge

Hi,
Have you got a DMM to measure some voltages?

Thanks.. Tom.. :)
Everything runs on smoke, let the smoke out, it stops running....

Grumpy_Mike

A solid state relay for DC is only a FET in a package and will be subject to a minimum trigger voltage. Look for a logic level FET to make the circuit. Most of those use 5V but some use 3V3.

flabombarda

#41
Jun 03, 2016, 03:02 pm Last Edit: Jun 03, 2016, 03:09 pm by flabombarda
I believe I already have one: FQP30N06L.pdf
http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Components/General/FQP30N06L.pdf
I found a different post where this is pointed as a 3.3 logic level mosfet.
http://forum.arduino.cc/index.php?topic=290272.0
May it work ?

ilguargua

Have you tried to read at least the very first lines of the linked DS?

FQP30N06L
60V LOGIC N-Channel MOSFET

As already pointed out, you need a P-Channel mosfet for high side switch. And also :

Features
•   32A, 60V, RDS(on) = 0.035Ω @VGS = 10 V

So it needs 10V of gate voltage to fully open. And 32 Amps to switch on an ESP8266 is like killing a fly with a bazooka!
I recently buy some of this : http://www.farnell.com/datasheets/2049228.pdf, and some adapters : http://www.farnell.com/datasheets/1919278.pdf, this ones sould works fine with 3.3 V.

Cheers, Ale.

be80be

I fulled with this today just for the fun of it and simple pnp 2n3906 swiching  3.3 volt on the esp2866 had no problems at all.

flabombarda

I ordered a P channel transistor and I expect to have this in the next few days to test the proposed circuit.

Thanks

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