[header] How to deal with a police polygraph test [title] Understand the various parts of the polygraph equipment. [step] This will help you appreciate what the machine is and is not capable of. When you sit down to take the exam, you will be fitted with a blood pressure cuff, a pneumograph, and two galvanometers. 
[substeps] A galvanometer is a finger plate that is placed on your fingers and that measures how much you perspire as a result of stress. A blood pressure cuff keeps track of your blood pressure.