Secondary Dominants Explained-understand them ONCE and FOR ALL! (hammered home for clarity!)

Secondary dominants are Dom. 7th chords that temporarily treat a diatonic chord as if it is a tonic. The V7 is always the 5th position (built upon the 5th note of the major scale.) V ALWAYS CAN resolve a 4th ABOVE or V below....however, it dosn't have to. It can resolve to a Majoe OR Minor. The secondary dominant resolves to the TARGET CHORD i.e. one of the triads siatonic to the given key.