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Topic: Difference between N-channel power MOSFET and 2N 7000-021 (Read 645 times) previous topic - next topic

redlazer

Hey guys,

I have an RGB LED Strip that I'm trying to get working. The tutorial I'm using calls for N-Channel power MOSFET's, and I have 2N 7000-021 Transistors.

I thought these were similar in form and function, but my setup doesn't appear to work, and I'm not sure why. They are the only difference between the tutorial and my setup, so I'm guessing it must be them.

I unfortunately don't know enough to say if they are different or not. I'd appreciate a tip or two!

Thanks in advance!

dc42

#1
Dec 01, 2012, 10:06 pm Last Edit: Dec 01, 2012, 10:07 pm by dc42 Reason: 1
The 2N7000 is a mosfet with a maximum continuous drain current rating of 200mA and Rds(on) @ Vgs=5V specified up to 50mA. So if your LED strip needs 200mA 50mA or less and you connect it correctly, it will probably be OK.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

redlazer

Hmm. I think that may be the problem then. Please correct me if I'm wrong - I'm still learning.

I'm using this RGB strip:

http://adafruit.com/products/285

And my power supply is 12V 2A. I have 20 segments. I seem to recall I needed 60mA..?

Maybe I'll try again but without the transistors.

Does my math check out?

dc42

The spec says 12V @ 60mA per segment and implies that segments are connected in parallel. So that's 1.2A for 20 segments. You definitely need a power mosfet for that.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.


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