Vernier Tech Info Library TIL #1467

Question

What is the timing precision of photogate measurements in LabPro or LabQuest?

Answer

LabPro makes timing measurements to a 400 ns resolution. You may need to increase the time decimal place display to see this much information.

LabQuest makes timing measurements to a 200 ns resolution, but the result is truncated to 1000 ns steps. You may need to increase the time decimal place display to see this much information.

However, for both interfaces this resolution is overkill due to parallax error. See American Journal of Physics, 57 (9) Sept 1989, p 840-844, for "Photogates: An Instrumental evaluation," by Mosca and Ertel.

For block to unblock timing measurements, the effective flag length is often 10% shorter than the physical flag length.

Created by: jgastineau on September 02 2005
Last updated by: jhopkins on March 03 2010