i need facts about a two-quadrants analog multiplier

 

Have you tried Google? There are 252,000 hits on the subject.

 

One way to learn more about analog multipliers is to examine the datasheet for a particular device.

Here is the datasheet for a four-quadrant multiplier that can be studied. With a four quadrant device you can design an analog multiplier with which you can choose the two quadrant in which you want to operate.

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