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I am new to the use of transistors and couldn't find exactly how to select the right transistor for this type of an application which is to control a 5m 5050 RGB LED strip with an Arduino. The LED strip has 4 pins (R/G/B/12V) so I would need 3 transistors for R,G and B. The LED strip has 300 LEDs (60LEDs/m) and each LED consumes 20mA max current so the max current through any transistor would be 6A. I believe the Arduino outputs at 5V so the input to the base of the transistor would be 5V.

I came across the NPN 2N2222 transistor however its datasheet shows the following which states that its max collector current is 600mA so I am led to believe that I would need a transistor with a higher collector current.

datasheet of the NPN 2N2222

I also found the TIP102 NPN transistor (datasheet) which is has a higher max collector current of 8A which is sufficient for its use. It also has a base voltage of 5V and a max collector-emitter voltage of 100V which is also sufficent.

datasheet of the NPN TIP102 transistor

I also came across the IRLZ34N MOSFET (datasheet) however am not familiar with MOSFETs.

Would the TIP102 transistor work for my use of controlling an LED strip with the 5V arduino?

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  • \$\begingroup\$ Don't confuse Absolute Maximum ratings with operational ratings. \$\endgroup\$ – Ignacio Vazquez-Abrams May 26 '18 at 19:58
  • \$\begingroup\$ @IgnacioVazquez-Abrams so should it be fine seeing that the maximum ratings are much above my use for it? \$\endgroup\$ – Chirag Galaiya May 26 '18 at 20:00
  • \$\begingroup\$ Go for a mosfet. \$\endgroup\$ – Andy aka May 26 '18 at 20:03
  • \$\begingroup\$ @Andyaka could you advice which one as I'm clueless in selecting them. Would the IRLZ34N work? \$\endgroup\$ – Chirag Galaiya May 26 '18 at 20:05
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    \$\begingroup\$ Bipolar transistors amplify current. You should design around 10mA max output current for an Arduino pin and you need 6 amps, so you need a transistor beta of 600 (beta is the current gain of the transistor). To get a beta this high you would almost certainly have to use a darlington transistor which is two transistors in series. A better idea would be to use a logic level mosfet, take a look at the irl540 or similar. \$\endgroup\$ – Dean Franks May 26 '18 at 20:07
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Choose a logic level type Nfet for a low side switch Source= 0V such that RdsOn*I^2=Pd is cool 😎 <0.25W without a heatsink .

It will probably be rated 10x the load current you plan to use. There are far more SMD choices.

Otherwise 😜🔥

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  • \$\begingroup\$ Thank you very much. Just to confirm the IRLZ34N should be fine? \$\endgroup\$ – Chirag Galaiya May 28 '18 at 12:04
  • \$\begingroup\$ if you analyze it thermally. RdsOn rises 50% at 100'C but 0.046Ω at Vgs=5V only at 25'C thus 6A * 0.046 *150% * 62'C/W= 25'C rise at 40'C internal ambient = 65'C passes the sniff test. But heatspread it if in a sealed box. Idmax=30A@25'C so 6x load, is OK if above is true. Tj=85'C max under any condition is OK. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 May 28 '18 at 12:16

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