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Old 06-04-2006, 01:24 AM   #1
repairs online
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Join Date: May 2006
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Default TRIAC BTA12 - Your thoughts, Please!!!


Have a TRIAC, ID: BTA12. Here is the URL for the datasheet:

The package is a TO-220AB Insulated, in other words it is packaged the same way as most HOTs. The only difference between HOTs and TRIACS is that , leg 1 from the left is Anode 1, leg 2, the middle leg is Anode 2, and leg 3 is the Gate.

On connecting a digital multimeter regardless of polarity between Anode 1 and Gate, the resistance is ~45 Ohms.

There is no reading between Anode 2 and Gate, infinite resistance, regardless of polarity.

Also, no reading between Anode 1 and Anode 2 regardless of polarity.

Now, if either positive or negative polarity is applied to Anode 1 and Anode 2 and the Gate is shorted to Anode 2, the multimeter reads ~45 Ohms.

Upon disconnecting the Gate from Anode 2, again the reading becomes infinite while the leads of the multimeter are in contact with Anode 1 and Anode 2.

The question is:

Should the reading continue to be ~45 Ohms after disconnecting the Gate from Anode 2, at least this what the theory tells me on testing Triacs, ( the resistance should continue , in this case, to be ~45 Ohms, provided the multimeter leads are in contact the Anode 1 and Anode 2) or

is the Triac faulty? and the reasons why.

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