Most people obtain their polygraph "knowledge" from researching the Internet, watching television, and watching movies. There have been a number of talk and reality shows that portray a polygraph test being done. In reality it would not be accurate to conduct a test in front of an audience or live air. In most cases these are staged for the audience and for effect.
Sometimes they are, but most of the time they are not.
When a highly qualified examiner conducts polygraphs for television, the exams are done off-camera before the show and can take several hours. The examiner may then re-enact a small portion of the exam for the audience, so what you see is not an actual polygraph test.
Precision Polygraph of Texas does not conduct polygraphs for media.