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I have a NodeMCU Dev Board that I would like to connect to a RGB Light strip to control over wifi. I have found a digram on the internet explaining how to connect it up. It includes a 500Ω resistor, but since I don't have any, I want to know if it is safe to not include the resistor and not fry anything.

Diagram: RGB Controller with ESP8266(NodeMCU) http://www.esp8266.com/viewtopic.php?f=11&t=12259

I would appreciate your response.

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This is the TIP122: -

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And, when driving the base, a resistor is usually needed especially if the emitter is connected to 0 volts because the base will form an impedance to 0 volts that looks like two forward biased diodes in series and this limits how much voltage can be applied.

Failing to put a resistor in series may cause the base driver to fail or overheat or take too much current and cause other problems. If you haven't got a 500 ohm resistor I'm sure a 470 ohm or 560 ohm will do just fine.

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  • 2
    \$\begingroup\$ @Username: 500 Ohms is not a standard value - use 470 or 510 Ohms. \$\endgroup\$ – Peter Bennett Jul 31 '17 at 15:28

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