For Blocked-to-Blocked and Unblocked-to-Unblocked transitions<\/b>
Vernier photogates have an electronic timing resolution of 1 microsecond. You will, however, typically get measurements with as much as +\/-25 millisecond variation. This is due to variations in optical-response tolerances of the photodiodes and the geometry of the object relative to the path it takes through the photogate.<\/p>\n
When using multiple Go Direct Photogates connected wirelessly, you will typically get measurements with +\/- 35 millisecond variation. This 10 millisecond difference is associated with the initialization of multiple device clocks when starting data collection. Two Go Direct Photogates daisy-chained together do not experience this added error as they are utilizing a single clock. (Daisy-chaining two Go Direct Photogates requires a Go Direct® Photogate Timing Cable<\/a> ( For Blocked-to-Unblocked and Unblocked-to-Blocked transitions<\/b> For a good discussion of these issues, see “Photogates: An instrument evaluation,” Eugene P. Mosca and John P. Ertel, Am. J. Phys. 57 (9), 840-844 (1989).<\/p>","protected":false},"excerpt":{"rendered":" For Blocked-to-Blocked and Unblocked-to-Unblocked transitionsVernier photogates have an electronic timing resolution of 1 microsecond. You will, however, typically get measurements with as much as +\/-25…<\/p>\n","protected":false},"author":8976,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[],"tags":[1420,1985,1984,1982,1983,7650,1981,1987,1986],"class_list":["post-1467","post","type-post","status-publish","format-standard","hentry","tag-accuracy","tag-accurate-accuracy-time","tag-labpro-labquest","tag-parallax","tag-photogate-error","tag-specification","tag-timing-precision","tag-uncertainty","tag-vpg-vpg-btd-gdx-vpg"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/posts\/1467","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/users\/8976"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/comments?post=1467"}],"version-history":[{"count":0,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/posts\/1467\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/media?parent=1467"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/categories?post=1467"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/tags?post=1467"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Due to differences in the optical-response of a photodiode when transitioning from unblocked-to-blocked compared to blocked-to-unblocked, photogate timing modes that utilize both blocked and unblocked events (for example, Gate Timing<\/b> and Gate and Pulse Timing<\/b>) will give significantly higher error in the timing measurements. Whenever possible, avoid using these timing options for data collection.<\/p>\n