What Does A Tremolo Do> If An Electric Guitar Has A Tremolo Bar Fitted Does That Prevent You From Drop Tuning The Guitar?

If an electric guitar has a tremolo bar fitted does that prevent you from drop tuning the guitar? - what does a tremolo do>

Looking to buy a new power, I looked like a tremolo bar installed. But I want the fall of the electric current, so that you can play certain songs. Hold the tremolo from the drop-tuning?