use of resister in this circuit diagram

Thread Starter

scirec

Joined Feb 1, 2024
1
1706771969656.png
how does current flow through these mosfets, is n chanell mosfet used for for both common cathode and anode circuits?
in this circuit instead of rgb led am using rgb strip so there would be common anode in it so the connection maybe different from picture
how should i make the connection so it doesnt end up in short circuit??
what is the use of the resistor here ?why is it connected to ground
 

Dodgydave

Joined Jun 22, 2012
11,318
Your led looks very likely it will blow up, the cathodes should have a series resistor , ( 330 ohms to 1K) and connected to the Drain terminals of the fets, , the gates go directly to the Arduino.


jl1qV.png
 
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Alec_t

Joined Sep 17, 2013
14,377
Welcome to AAC!
If the resistors you are talking about are each connected between a MOSFET gate and source then their purpose is to ensure the MOSFET gate-source voltage is pulled low in the absence of well-defined control signals from the Uno, e.g when the Uno is first powered up. MOSFET gates should never be left 'floating'.
 

panic mode

Joined Oct 10, 2011
2,808
should be something like this IF your RGB LED is common Anode... But i don't recall seeing one. I think they tend to be common Cathode...

1706847039615.png
 

Tonyr1084

Joined Sep 24, 2015
7,956
My RGB LED's are common anode. However, I have colored LED strips that are common cathode and are controlled by pulling the LED to ground through a control circuit. In other words, an N type FET should be a source follower. At least that's my understanding of it. FET's remain a confusing beast to me. I have them but don't often use them.

Also, your control pots are hugely confusing and very hard to follow. But I don't think that's the focus of this thread.
[edit] this is what I make of your control pots:
1706888275976.png
 
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