Cov tub ntxhais hlau nplaum nyob rau hauv qhov sib thooj hloov pauv hloov hauv oscillation Circuit Court los ntawm kev nyob ze ntawm cov hlau, thiab tom qab ntawd tso tawm cov teeb liab. Nws yog qhov tsim nyog rau kev kuaj xyuas cov khoom hlau ntawm qhov ze ze.
Lub photoelectric hloov emits lub teeb beam mus rau saum npoo ntawm cov khoom, thiab ces bounces rov qab mus rau qhov kawg ntawm qhov kev hloov. Qhov kawg tau txais tau txais cov teeb liab kho qhov muag thiab hloov nws mus rau hauv lub teeb liab hluav taws xob los tsim cov khoom tso tawm. Haum rau kev ntes cov khoom ntawm qhov deb.