Can someone also provide the terminal considerations in the anti-parallel configuration, if such a design is practically possible.
The quick answer is yes, in principle.
We used to do this before triacs were common place.
There are design issues though.
Mainly in how you trigger the device.
The Lamina T51-100-14 is rated at 1400 volts 100A, but needs 150mA of trigger current Iin the first quadrant. However, unlike triacs that trigger in the 3rd quadrant, the scr needs positive and negative trigger voltage; one for each scr.
You then need to get the right size for the jog. 600V ac supply gives about 850 Vpeak
DIAC is considered as back to back DIODs, and TRIAC as back to back SCRs, hence can be used where and when needed, as back to back(anti parallel) combination, insted of using two diods or SCRs. Only the rating and specification should be matched as required or within the range to used as per manual......
Dear Bhupendra,
Although the pn junctions of a diac may look like two back to back diodes, a diac 's function is completely different; it is an avalanche device. Normally open circuit until the voltage threshold is exceeded (either + or -) , it then becomes a near short circuit until the lower current threshold is reached, when it goes open circuit again.
Diac's usually avalanche at around 30Volts and are used to trigger Triacs. Here is one example: http://www.taitroncomponents.com/catalog/Datasheet/DB3.pdf
They will not work as back to back diodes due to the avalanche characteristic. A more accurate description would be a low avalanche Triac with no trigger connection.
Diacs are relatively low current devices (2A typically), I am not aware of any high current Diacs that can replace SCR's or Triacs. In any case, they have no trigger electrode
Best Regards
Paul
I have not suggested Diacs, and I am sure, for his rateing of Triac, two back to back SCRs circuit will work.
The SCR should be rated at 1200v & the current rating of each SCR should be> atleast 0.707 of the rms load current.Pulse transformers could be used to trigger the SCR"s. [email protected]
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