[review] optotriac

[michal_w]

Hello colleagues,
I need to make a circuit to turn on a load resistor and then turn off ( I have to measure voltage with and witout load).
I've attached my scheme which I want to use. The load resistor is R2. I want to connect R1 with microcontroller.
Is it correct?

 

[MrAl]

Hi,

Im not sure if those opto's you are talking about using here are made for continuous load handling like that. Some of them are made just for firing a regular triac. You might want to double check the specs.

 

[michal_w]

So, what should I use? I want to turn on and turn off the load resistor when I want, not when it cross zero (like using thyrisotrs or triacs).

 

[MrAl]

Hi again,

What kind of load are you trying to drive, it is just a resistor? What value?

 

[michal_w]

Only resistor 100 Ohm - 1 kOhm.

 

[crutschow]

The MOC3020 can only switch 100mA max. so the maximum V1 supply voltage you could use with a 100 ohm resistor would be 10V. If you want to switch more current than that you can go with a larger DC output solid-state relay.

Edit: The MOC3020 also has a triac output so it will switch at the zero crossing. If you want it to switch otherwise you will need a DC output solid-state relay.

 

[MrAl]

Only resistor 100 Ohm - 1 kOhm.

Hi again,

Is your source voltage really AC or could you use DC, and what level is it (volts)?

 

[michal_w]

I have to measure the output voltage of a transformer with and without load resistance.
Voltage range is 10-15 V.

 

[Mr RB]

A relay?

Or a FET or transistor that connects the resistor to the transformer secondary using a diode bridge?

 

[michal_w]

Hello,
thanks for your replies.
If I will use solid state relay is it possible to switch off the load resistor in any moment of the time (like in attached picture) ?

 

[crutschow]

Hello,
thanks for your replies.
If I will use solid state relay is it possible to switch off the load resistor in any moment of the time (like in attached picture) ?

As I stated in my previous post, you need to use a DC output type solid-state relay.

 

[4pyros]

As I stated in my previous post, you need to use a DC output type solid-state relay.

Ya but thats an AC wave form in his pic. I must be confused.

 

[crutschow]

Ya but thats an AC wave form in his pic. I must be confused.

A DC output solid-state relay is usually bipolar so it will also control AC.

 

[michal_w]

Hello,
thanks for your replies. I've bought AQY414 and now I'm designing PCB.