problem of function of moc3021

[nonomomo]

I used the MOC3021 to drive a load (the diagram below) May I have two quetion I want someone to help me:
1) why did not I obtained the output voltage as the input voltage but it is decalé the delay I determined
2) I want a circuit that is controlled linearement (4-20mA) not controlled by on / off

 

[FvM]

1. The delay is mainly caused by an unsuitable high gate resistor R1 value of 2k.
2. Triac switches only provide on/off control. You might think about tranlating the 4-20 mA control signal into a phase angle.

 

[nonomomo]

thanks , but the problem when i change the value of R1 , i will not find any thing about the output,
but have you any idea about how to realize the power circuit command by linear input?

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thanks , but the problem when i change the value of R1 , i will not find any thing about the output,
but have you any idea about how to realize the power circuit command by linear input?

 

[FvM]

i will not find any thing about the output

Means what? According to the screenshot, the statement isn't understandable.

 

[nonomomo]

i used the moc3021 to command AC load but the problem is i coudn't obtains in output a very output as a input but retaired by duty ratio and the subject how to realise a power circuit not commanded by on/off such as this circuit , but it will command by a linear input (0 range to 5v)

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hi FvM: look at the red signal must be such as the yellow signal .
i used the moc3021 to command AC load but the problem is i coudn't obtains in output a very output as a input but retaired by duty ratio and the subject how to realise a power circuit not commanded by on/off such as this circuit , but it will command by a linear input (0 range to 5v)

[/QUOTE]

 

[FvM]

As said, phase angle control is the solution, delaying the trigger impulse with respect to AC voltage zero crossing. There are different ways to implement it, e.g. microcontroller, LM555 monoflop or dedicated controller ICs and tons of previous Edaborad threads about phase angle control.

 

[nonomomo]

thanks for your help, i used the pic16f to generate the PWM and i found the same signal the Vout AC as Vin at amplitude , but the other problem i found it , when i changed the duy ratio by the pic18f , the signal Vout didn't change like that the picture !
https://obrazki.elektroda.pl/1606631800_1367519564.jpg

 

[FvM]

I see what you mean. Unfortunately I can explain why this happens, it might be a problem of the Proteus models.

 

[nonomomo]

i don' think that!

 

[FvM]

You can narrow down the problem by viewing individual voltage and current waveforms. Or post the *.dsn and *.hex files.

 

[deepakchikane]

Which is this software of simulations??

 

[nonomomo]

the seftware is logiciel porteus ISIS