I know there are other posts like this but none have been correctly answered. I have this circuit, and I would like to control it with an Arduino without a relay. Is this possible?

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  • Do you want to control the external 9V at about the 10-20mA that the LED is drawing? Use an NPN transistor as in electronics.stackexchange.com/questions/95089/… – Dave X Jan 25 '17 at 2:38
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    none have been correctly answered - oh? Where? – Nick Gammon Jan 25 '17 at 5:22
  • If you are asking if the Arduino can blink an LED, then yes, it is very good at that. And you don't need a relay. – Nick Gammon Jan 25 '17 at 5:22
  • It will be far easier if you'd just describe your intended application instead of making us play 20-questions and feeding us little bits at a time. You've finally told us it's not an LED but a lamp. I'm not going to ask you what kind of lamp and please don't answer it to this comment. Update your question to say what your ultimate goal is, with specs about the lamp, the voltage, whatever else. If you don't want to disclose it, OK, but understand that what you've been given so far is all you can get without a fuller description. – JRobert Jan 25 '17 at 14:00

That is just an LED... you can simply connect the LED anode to an Arduino IO pin and the cathode through a 330Ohms resistor to ground.

Then just write the Arduino sketch to toggle the IO on and off.

Check the blink example sketch.

  • no I used this as an analogy of a bigger circuit. I wanted to know if without a relay it is possible to turn a circuit on and off with the arduino. – JulesTheGodOfMC Jan 25 '17 at 9:23
  • Without details on the circuit in question it is impossible to provide an accurate response. – Andre Courchesne Jan 25 '17 at 10:51
  • What if I just told you it was a lamp. I cut the wires and I want to be able to turn it on and off using the arduino, without any relay, or motor – JulesTheGodOfMC Jan 25 '17 at 13:18
  • You won't be able to control 120v directly from the Arduino, you need a switch circuit that is able to handle the load. For a 120v AC application like a lamp, I would either go for a electromechanical or solid-state relay or a mosfet circuit (something like this: bildr.org/2012/03/rfp30n06le-arduino) – Andre Courchesne Jan 25 '17 at 13:55

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