Optocoupler Connection

[poxkix]

Will my circuit connection work?
At default state, the MCU pin is at state 0. If the MCU pin changes state to 1 it activates the 12v solenoid.
Does the Optocoupler make any difference if it is there or not?

 

[enjunear]

As you have it connected, no, that will not work. The NPN inside the optocoupler will try to draw current out of the base of your 2N2222, which is like trying to reduce the voltage on the base of the 2N2222, turning it off. What you need to do is remove the 2N2222A and replace it with the NPN transistor inside the optocoupler. Pin 16 is the collector and pin 15 is the emitter node, just delete the 2N2222A and replace it with the opto's output transistor.

Look over the spec sheet to see what your nominal voltage and current are for the input of the optocoupler, so that your MCU output voltage across 1k won't blow out the LED inside. Also, check the current handling capability of the output of the optocoupler, to ensure that it can sink enough current to energize the relay. You may need to use a second transistor to get additional current gain. If that is the case, I'd use a PNP to compliment the optocoupler's output.

 

[poxkix]

As you have it connected, no, that will not work. The NPN inside the optocoupler will try to draw current out of the base of your 2N2222, which is like trying to reduce the voltage on the base of the 2N2222, turning it off. What you need to do is remove the 2N2222A and replace it with the NPN transistor inside the optocoupler. Pin 16 is the collector and pin 15 is the emitter node, just delete the 2N2222A and replace it with the opto's output transistor.
Look over the spec sheet to see what your nominal voltage and current are for the input of the optocoupler, so that your MCU output voltage across 1k won't blow out the LED inside. Also, check the current handling capability of the output of the optocoupler, to ensure that it can sink enough current to energize the relay. You may need to use a second transistor to get additional current gain. If that is the case, I'd use a PNP to compliment the optocoupler's output.

Is that so sir? Okay, I will remove the 2N2222A.
Sir, I have the data sheet but I'm still a beginner at reading the the datasheet.
Any of these information suites what you told me to look for?

 

[Li_ereunpisan]

Will my circuit connection work?
At default state, the MCU pin is at state 0. If the MCU pin changes state to 1 it activates the 12v solenoid.
Does the Optocoupler make any difference if it is there or not?

View attachment 69608

maybe you should add a pullup resistor 10k on pin colector opto

 

[poxkix]

maybe you should add a pullup resistor 10k on pin colector opto

How does it help with the circuit?

 

[Li_ereunpisan]

How does it help with the circuit?

maybe this could help
View attachment opto.bmp

 

[poxkix]

maybe this could help
View attachment 69616

Thanks sir. What is that pin 6 for?
Before I checked your reply I tried searching for more answers and constructed a new one. Can you check sir?

 

[dselec]

---------- Post added at 11:35 ---------- Previous post was at 11:32 ----------

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maybe you should add a pullup resistor 10k on pin colector opto

Yes it will work... just add another resistor 5k-10 k between +vcc 1nd pin 10 of isolator.
U may need to invert your opto input depends what u want.

 

[poxkix]

Yes it will work... just add another resistor 5k-10 k between +vcc 1nd pin 10 of isolator.
U may need to invert your opto input depends what u want.

I think I'm confused sir. How does pin 10 of isolator help in the circuit?

 

[dselec]

Will my circuit connection work?
At default state, the MCU pin is at state 0. If the MCU pin changes state to 1 it activates the 12v solenoid.
Does the Optocoupler make any difference if it is there or not?

View attachment 69608

Yes it will work... just add another resistor 5k-10 k between +vcc 1nd pin 10 of isolator.
U may need to invert your opto input depends what u want.

---------- Post added at 11:40 ---------- Previous post was at 11:37 ----------

Your transistor base needs bais the resistor will supply it and relay will energize, when your mpu will supply logic high "1" the opto will short the bias and relay release.
another option is add nothing just change transistor to pnp 2n2907 and change emmiter with collector

 

[Li_ereunpisan]

Thanks sir. What is that pin 6 for?
Before I checked your reply I tried searching for more answers and constructed a new one. Can you check sir?
View attachment 69618

it is just the equation of the type of optocoupler..... pin 6 is not used / not conected

 

[poxkix]

Yes it will work... just add another resistor 5k-10 k between +vcc 1nd pin 10 of isolator.
U may need to invert your opto input depends what u want.
---------- Post added at 11:40 ---------- Previous post was at 11:37 ----------
Your transistor base needs bais the resistor will supply it and relay will energize, when your mpu will supply logic high "1" the opto will short the bias and relay release.
another option is add nothing just change transistor to pnp 2n2907 and change emmiter with collector

Okay. Thanks sir. I think I understand what you are teaching me.

it is just the equation of the type of optocoupler..... pin 6 is not used / not conected

Oh.. So the circuit you gave me will serve the purpose that I want?