TRIAC 4 quadrant test circuit doesn't work

[HDaniel]

Hello,

In attachement you'll find a testing circuit for a TRIAC. U1 should be adjusted between 0 up to 2.7V (so the Ug voltage is between 0 and 0.85V). The purpose is to find out when the TRIAC will starts to work. By changing U1 and U2 polarity you could do this in all the 4 quadrant's.

I tried it but the circuit doesn't work.

Normally it should work fo a TIC226, but this one isn't in the Multisim database.

So i changed it with the MAC228-A6 TRIAC.

Could someone find the error, or give me a working testing circuit (4 quadrant's) for a TRIAC?

Kind regards,

Daniel

[ThiCop]

Hello HDaniel,

I've looked at your schematic, but it's not a 100% clear what your question is.

Can you post what the original schematic looks like that you have to simulate?

U1 seems to be a fixed DC voltage (12V) based on your schematic.

Therefor I don't directly see the link between this fixed DC Voltage and the adjustion you're talking about.

I don't see that adjustion in the schematic.

If it is there, then please point me towards it.

Thanks in advance for your feedback!

[HDaniel]

Hello,

Thank you for you reply.

Power supply V1 should be fix on 12 Volt.

Power supply V2 should be adjusted between 0 to 2.70 Volt (so Ug= 0 Volt up to 0.85 Volt)

Purpose is to check at wich level of Ug the TRIAC starts to conduct. (Ut <--> Ug caracteristic, and this for the 4 quadrants). So V1 and V2 will be changed in polarity. It isn't a problem of just grounding the circuit.

It just doesn't work.  

In attachement a drawing.

[johnsold]

I am not sure what the E1 and E2 represent.

There should be some resistance between U2 and the TRIAC. Without any resistance the current will become very large or the model of the TRAIC may fail.

Lynn

[HDaniel]

E1 and E2 are 2 lamps (or V2 is 24Volt and we use 2 lamps 12V/10W , or we use 1 lamp 12V10W and V2 is 12Volt)

[ThiCop]

After a week of courses I'm back at the office.

Did you try it with the added resistance?

[HDaniel]

As mentioned before, i don't need an added resistance because E1 and E2 are lamp(s) 12V/10W. Regards, Daniel

[ThiCop · Accepted solution]

Hello Daniel,

I have been able to check your code again and we'll first check your schematic without any extra resistances.

Can you do the following things?

- Provide a ground for your schematic. (preferably at the common '-'-side of your sources)

- Provide a discharge capacity for both of your voltage sources (especially for the varying one)

Can it be that one of the lamps is missing in the schematic in your first post?

[HDaniel]

Hello,

I adjusted the circuit as you proposed and now it's working.

The only strange thing is that i got the same results when i'am testing the 4 quadrants.

V1 = +12V and V2=+7.9V (Ug=2.519V) --> TRIAC starts to work

V1 = +12V and V2=-7.9V (Ug=2.519V) -> TRIAC starts to work

V1 = -12V and V2=-7.9V (Ug=2.519V) --> TRIAC starts to work

V1=-12V and V2=+7.9V (Ug=2.519V) --> TRIAC starts to work

The current i have to the gate is 0.444 µA what is quiet low i think.

I expected to see a difference of level of Ug to get the TRIAC conducting, depending on the quadrant i'am esting, but i receive 4 times the same result.

But after all it's working.

In attachment the adjusted circuit.