About SIDAC

[alok1982]

Hi! all,
I think many of you know that SIDAC stand's for "SIlicon Diode for Alternate Current". If i am not wrong then it is also called as SIDACtor. Can any one tell me how SIDAC works. After getting the positive answer i will put a circuit diagram here in which a SIDAC is used. Then we will go for further discussion on it's (SIDAC) working according to this schematic.

 

[Spyker]

Yes today is the first time that I heard of this components and it might be the missing component that I am looking for.

Wikipedia:
The SIDAC is a less common electrically equivalent device, the difference in naming being determined by the manufacturer. In general, SIDACs have higher breakover voltages and current handling.

The SIDAC, or Silicon Diode for Alternating Current, is another member of the thyristor family. Also referred to as a SYDAC (Silicon thYristor for Alternating Current), bi-directional thyristor breakover diode, or more simply a bi-directional thyristor diode, it is technically specified as a bilateral voltage triggered switch. Its operation is similar to that of the DIAC; the distinction in naming between the two devices being subject to the particular manufacturer. In general, SIDACs have higher breakover voltages and current handling capacities than DIACs.

The operation of the SIDAC is quite simple and is functionally similar to that of a spark gap. The SIDAC remains nonconducting until the applied voltage meets or exceeds its rated breakover voltage. Once entering this conductive state, the SIDAC continues to conduct, regardless of voltage, until the applied current falls below its rated holding current. At this point, the SIDAC returns to its initial nonconductive state to begin the cycle once again.

Somewhat uncommon in most electronics, the SIDAC is relegated to the status of a special purpose device. However, where part-counts are to be kept low, simple relaxation oscillators are needed, and when the voltages are too low for practical operation of a spark gap, the SIDAC is an indispensable component.

Similar devices, though usually not functionally interchangeable with SIDACs, are the Thyristor Surge Protection Devices (TSPD), SIDACtors, or the now-obsolete Surgector. These are designed to tolerate large surge currents for the suppression of overvoltage transients

 

[Arkham00]

I can't understand the difference between:

• SIDAC
• DIAC
• two zener diodes connected back to back in series
• varistor

All these devices seem to have almost the same V/I curve.

 

[alok1982]

Thank You!. Many just visit but didn't give answer. Well, finally get nice answer.