Thyristor (SCR) Problem

[AliRazoR]

Hi,

i am using thyristor (scr), TIC 106M, when i use DC for both gate and anode no problem but when i want to use AC(220 v or 12 v) the Lamp is on without firing the gate!
i connect 220 v to lamp and from lamp to anode pin of thyristor and cathode pin to ground.

thanks in advance

 

[FvM]

Are you using the thyristor according to the specification, e.g. placing a gate-cathode resistor? TIC106 has a sensitive gate, it's supposed to trigger spontaneous with floating gate terminal.

 

[_Eduardo_]

TIC106 is gate sensitive --> you cannot leave the gate floating.

 

[AliRazoR]

i did not connect the gate, only i connected a 220 v lamp to anode and ground to cathode, and the lamp was glowing.

---------- Post added at 18:07 ---------- Previous post was at 18:05 ----------

can i connect 5v dc to the gate? (220 v to anode)

 

[_Eduardo_]

Read the datasheet please.

 

[AliRazoR]

one question about datasheet what is VAA?

 

[FvM]

Read the datasheet please.

Yes, that's the straightforward way.
You surely need a current limiting resistor for a 5 V trigger source. And place a gate-cathode resistor of 1 k to keep the thyristor off without a trigger voltage.

 

[FvM]

one question about datasheet what is VAA?

I think, it's the test circuit's supply voltage, connected to the anode through a resistor.

 

[AliRazoR]

hi
i want to use 12 v ac,for dimmer. can any one told me how i can find conduction angle?is this formula correct for 0 to 90 degree control(simple RC control circuit):tan(a)=2wRC???

thanks in advance