If you thought this...

Do they have the same meaning? Is there any difference between them? Is the first sentence in second conditional too? Sometimes I see people use present tense in the "if" part and "would/might" in the second part. Will that structure also count as "second conditional"? I mean: If+present simple>>would+base verb.

1) If you think this phrase means to blow on someone, you would be mistaken.

2) If you thought this phrase means to blow on someone, you would be mistaken.