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I want to take an audio signal from a smartphone's 3 mm jack plug, pass it on to a 4N25 optocoupler,, and get the sound from an 8 Ω speaker. I don't know how to connect them to each other. Can you help me?

ocrdu
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Osman Efe
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    It's not as simple as just connecting them. You'll need additional components to amplify the signal after the optocoupler. And the optocoupler is only linear in current, while the audio out will be a voltage signal, so you'll need to use some method of converting a voltage to a current. And the optocoupler is only *approximately* linear at all, so you'll need to figure out how much distortion you can tolerate. – Hearth Oct 01 '22 at 23:51
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    use a transformer instead of an optocoupler, – Jasen Слава Україні Oct 02 '22 at 00:03
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    Why do you need the optocoupler? – Justme Oct 02 '22 at 00:12
  • İt is my first step of finishing project and ı should use an optocoupler. – Osman Efe Oct 02 '22 at 10:22
  • I dont understand what should ı actualy do (heart) – Osman Efe Oct 02 '22 at 10:26
  • Why do you want to use an optocoupler to connect a speaker to a phone's earphone output? There's no normal use for an optocoupler in that circuit. You can connect a small eight ohm speaker directly to the earphone output with no problem. – JRE Oct 02 '22 at 13:00
  • The actual aim is voice transmiting by light. And an optocoupler working like that. A LED and a phototransistor. For that reason it is my first step of finishing project. Firstly ı need to pass the voice on optocoupler and then use a LED and a phototransistor instead of optocoupler. – Osman Efe Oct 03 '22 at 14:27
  • I can create a circuit to amplify the Signal but ı dont know how to connect 3 mm Jack to transistor or directly to the optocoupler and how to connect speaker. – Osman Efe Oct 04 '22 at 00:14

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