No current through AC optocoupler

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I am just testing this component MOC3021 opto-isolator, it's datasheet can be found here.

This is my circuit in proteus :

Please forgive me for my ignorance of electronics, I have my background in computer science .

I tried the whole day yesterday trying to make out what's written about it in the datasheet, the point of connections were easy to understand, rest I don't know much. However, I did learn a lot and welcome to accept more.

However as you can see the LED didn't glow, now for one thing I know it's an AC opto-isolator but shouldn't current flow from one of the diodes of the DIAC ?

Thanks a lot :)

Sizu

ac opto-isolator

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Sizu Taylorventuresllc

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up vote
1
down vote

favorite

I am just testing this component MOC3021 opto-isolator, it's datasheet can be found here.

This is my circuit in proteus :

Please forgive me for my ignorance of electronics, I have my background in computer science .

I tried the whole day yesterday trying to make out what's written about it in the datasheet, the point of connections were easy to understand, rest I don't know much. However, I did learn a lot and welcome to accept more.

However as you can see the LED didn't glow, now for one thing I know it's an AC opto-isolator but shouldn't current flow from one of the diodes of the DIAC ?

Thanks a lot :)

Sizu

ac opto-isolator

share

asked 2 hours ago

Sizu Taylorventuresllc

61

New contributor

Sizu Taylorventuresllc is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

add a comment | 

up vote
1
down vote

favorite

up vote
1
down vote

favorite

I am just testing this component MOC3021 opto-isolator, it's datasheet can be found here.

This is my circuit in proteus :

Please forgive me for my ignorance of electronics, I have my background in computer science .

I tried the whole day yesterday trying to make out what's written about it in the datasheet, the point of connections were easy to understand, rest I don't know much. However, I did learn a lot and welcome to accept more.

However as you can see the LED didn't glow, now for one thing I know it's an AC opto-isolator but shouldn't current flow from one of the diodes of the DIAC ?

Thanks a lot :)

Sizu

ac opto-isolator

share

asked 2 hours ago

Sizu Taylorventuresllc

61

New contributor

Sizu Taylorventuresllc is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

I am just testing this component MOC3021 opto-isolator, it's datasheet can be found here.

This is my circuit in proteus :

Please forgive me for my ignorance of electronics, I have my background in computer science .

I tried the whole day yesterday trying to make out what's written about it in the datasheet, the point of connections were easy to understand, rest I don't know much. However, I did learn a lot and welcome to accept more.

However as you can see the LED didn't glow, now for one thing I know it's an AC opto-isolator but shouldn't current flow from one of the diodes of the DIAC ?

Thanks a lot :)

Sizu

ac opto-isolator

ac opto-isolator

share

asked 2 hours ago

Sizu Taylorventuresllc

61

New contributor

Sizu Taylorventuresllc is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share

asked 2 hours ago

Sizu Taylorventuresllc

61

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Sizu Taylorventuresllc is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share

share

asked 2 hours ago

Sizu Taylorventuresllc

61

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Sizu Taylorventuresllc is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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asked 2 hours ago

Sizu Taylorventuresllc

61

asked 2 hours ago

Sizu Taylorventuresllc

61

61

New contributor

Sizu Taylorventuresllc is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

New contributor

Sizu Taylorventuresllc is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

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Check out our Code of Conduct.

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3 Answers
3

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up vote
2
down vote

You have two small problems:

No resistor in series with the opto led. So the current is not limited, and will burn the opto if you try in real life

A voltage source too low to light a blue LED. Such LED typically require about 3 to 3.5V. You have 1.5V on this side which is far from sufficient. With a 100 ohm resistor, something like 4.5V would give something like 10-15mA.

share|improve this answer

answered 2 hours ago

dim

12.7k22365

add a comment | 

up vote
1
down vote

You've got three problems.

1: no current limit on the MOC3021 LED, with 5V there the LED inside the MOC3021 will not last long, add 220 ohms in series with the input.

2: not enough voltage on the output. The output is is phototriac which has a forwards voltage drop of 1 to 1.5V -
to light the blue LED you want 3V or so and a resistor to limit current, 9V with a 470 ohm resistor in series would be a good starting point

3: the output is a triac, once triggered on it will continue to conduct until something else stops the current - using an AC supply to power the output side circuit would help here.

share|improve this answer

edited 47 mins ago

answered 1 hour ago

Jasen

8,7671327

• 
  
  
  

  
  

  
  
  
  
  
  

  
  You're right, I didn't even realize it was a triac output.
  – dim
  49 mins ago
  

  
  
  
  

add a comment | 

up vote
0
down vote

In addition to what dim commented, Your voltage source BAT2 has the wrong polarity.
The LED D2 is now in reverse bias by the voltage source BAT2. You could change polarity of either BAT2 of LED D2 in order to let current flow throug the LED when MOC3021 is enabled by the primary side.

share|improve this answer

answered 1 hour ago

Sparkgap

11

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3 Answers
3

active

oldest

votes

3 Answers
3

active

oldest

votes

active

oldest

votes

active

oldest

votes

up vote
2
down vote

You have two small problems:

No resistor in series with the opto led. So the current is not limited, and will burn the opto if you try in real life

A voltage source too low to light a blue LED. Such LED typically require about 3 to 3.5V. You have 1.5V on this side which is far from sufficient. With a 100 ohm resistor, something like 4.5V would give something like 10-15mA.

share|improve this answer

answered 2 hours ago

dim

12.7k22365

add a comment | 

up vote
2
down vote

You have two small problems:

No resistor in series with the opto led. So the current is not limited, and will burn the opto if you try in real life

A voltage source too low to light a blue LED. Such LED typically require about 3 to 3.5V. You have 1.5V on this side which is far from sufficient. With a 100 ohm resistor, something like 4.5V would give something like 10-15mA.

share|improve this answer

answered 2 hours ago

dim

12.7k22365

add a comment | 

up vote
2
down vote

up vote
2
down vote

You have two small problems:

No resistor in series with the opto led. So the current is not limited, and will burn the opto if you try in real life

A voltage source too low to light a blue LED. Such LED typically require about 3 to 3.5V. You have 1.5V on this side which is far from sufficient. With a 100 ohm resistor, something like 4.5V would give something like 10-15mA.

share|improve this answer

answered 2 hours ago

dim

12.7k22365

You have two small problems:

No resistor in series with the opto led. So the current is not limited, and will burn the opto if you try in real life

A voltage source too low to light a blue LED. Such LED typically require about 3 to 3.5V. You have 1.5V on this side which is far from sufficient. With a 100 ohm resistor, something like 4.5V would give something like 10-15mA.

share|improve this answer

answered 2 hours ago

dim

12.7k22365

share|improve this answer

share|improve this answer

answered 2 hours ago

dim

12.7k22365

answered 2 hours ago

dim

12.7k22365

answered 2 hours ago

dim

12.7k22365

12.7k22365

add a comment | 

add a comment | 

up vote
1
down vote

You've got three problems.

1: no current limit on the MOC3021 LED, with 5V there the LED inside the MOC3021 will not last long, add 220 ohms in series with the input.

2: not enough voltage on the output. The output is is phototriac which has a forwards voltage drop of 1 to 1.5V -
to light the blue LED you want 3V or so and a resistor to limit current, 9V with a 470 ohm resistor in series would be a good starting point

3: the output is a triac, once triggered on it will continue to conduct until something else stops the current - using an AC supply to power the output side circuit would help here.

share|improve this answer

edited 47 mins ago

answered 1 hour ago

Jasen

8,7671327

• 
  
  
  

  
  

  
  
  
  
  
  

  
  You're right, I didn't even realize it was a triac output.
  – dim
  49 mins ago
  

  
  
  
  

add a comment | 

up vote
1
down vote

You've got three problems.

1: no current limit on the MOC3021 LED, with 5V there the LED inside the MOC3021 will not last long, add 220 ohms in series with the input.

2: not enough voltage on the output. The output is is phototriac which has a forwards voltage drop of 1 to 1.5V -
to light the blue LED you want 3V or so and a resistor to limit current, 9V with a 470 ohm resistor in series would be a good starting point

3: the output is a triac, once triggered on it will continue to conduct until something else stops the current - using an AC supply to power the output side circuit would help here.

share|improve this answer

edited 47 mins ago

answered 1 hour ago

Jasen

8,7671327

• 
  
  
  

  
  

  
  
  
  
  
  

  
  You're right, I didn't even realize it was a triac output.
  – dim
  49 mins ago
  

  
  
  
  

add a comment | 

up vote
1
down vote

up vote
1
down vote

You've got three problems.

1: no current limit on the MOC3021 LED, with 5V there the LED inside the MOC3021 will not last long, add 220 ohms in series with the input.

2: not enough voltage on the output. The output is is phototriac which has a forwards voltage drop of 1 to 1.5V -
to light the blue LED you want 3V or so and a resistor to limit current, 9V with a 470 ohm resistor in series would be a good starting point

3: the output is a triac, once triggered on it will continue to conduct until something else stops the current - using an AC supply to power the output side circuit would help here.

share|improve this answer

edited 47 mins ago

answered 1 hour ago

Jasen

8,7671327

You've got three problems.

1: no current limit on the MOC3021 LED, with 5V there the LED inside the MOC3021 will not last long, add 220 ohms in series with the input.

2: not enough voltage on the output. The output is is phototriac which has a forwards voltage drop of 1 to 1.5V -
to light the blue LED you want 3V or so and a resistor to limit current, 9V with a 470 ohm resistor in series would be a good starting point

3: the output is a triac, once triggered on it will continue to conduct until something else stops the current - using an AC supply to power the output side circuit would help here.

share|improve this answer

edited 47 mins ago

answered 1 hour ago

Jasen

8,7671327

share|improve this answer

share|improve this answer

edited 47 mins ago

edited 47 mins ago

edited 47 mins ago

answered 1 hour ago

Jasen

8,7671327

answered 1 hour ago

Jasen

8,7671327

answered 1 hour ago

Jasen

8,7671327

8,7671327

• 
  
  
  

  
  

  
  
  
  
  
  

  
  You're right, I didn't even realize it was a triac output.
  – dim
  49 mins ago
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  

  
  
  
  
  
  

  
  You're right, I didn't even realize it was a triac output.
  – dim
  49 mins ago
  

  
  
  
  

You're right, I didn't even realize it was a triac output.
– dim
49 mins ago

You're right, I didn't even realize it was a triac output.
– dim
49 mins ago

add a comment | 

up vote
0
down vote

In addition to what dim commented, Your voltage source BAT2 has the wrong polarity.
The LED D2 is now in reverse bias by the voltage source BAT2. You could change polarity of either BAT2 of LED D2 in order to let current flow throug the LED when MOC3021 is enabled by the primary side.

share|improve this answer

answered 1 hour ago

Sparkgap

11

New contributor

Sparkgap is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

add a comment | 

up vote
0
down vote

In addition to what dim commented, Your voltage source BAT2 has the wrong polarity.
The LED D2 is now in reverse bias by the voltage source BAT2. You could change polarity of either BAT2 of LED D2 in order to let current flow throug the LED when MOC3021 is enabled by the primary side.

share|improve this answer

answered 1 hour ago

Sparkgap

11

New contributor

Sparkgap is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

add a comment | 

up vote
0
down vote

up vote
0
down vote

In addition to what dim commented, Your voltage source BAT2 has the wrong polarity.
The LED D2 is now in reverse bias by the voltage source BAT2. You could change polarity of either BAT2 of LED D2 in order to let current flow throug the LED when MOC3021 is enabled by the primary side.

share|improve this answer

answered 1 hour ago

Sparkgap

11

New contributor

Sparkgap is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

In addition to what dim commented, Your voltage source BAT2 has the wrong polarity.
The LED D2 is now in reverse bias by the voltage source BAT2. You could change polarity of either BAT2 of LED D2 in order to let current flow throug the LED when MOC3021 is enabled by the primary side.

share|improve this answer

answered 1 hour ago

Sparkgap

11

New contributor

Sparkgap is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share|improve this answer

share|improve this answer

answered 1 hour ago

Sparkgap

11

New contributor

Sparkgap is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

answered 1 hour ago

Sparkgap

11

answered 1 hour ago

Sparkgap

11

11

New contributor

Sparkgap is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

New contributor

Sparkgap is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

Sparkgap is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

add a comment | 

add a comment | 

Sizu Taylorventuresllc is a new contributor. Be nice, and check out our Code of Conduct.

 

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