่จ้ฒใฟใคใใผใฏไธๅฎๆ้ใใจใซ็ดใใผใใซ็นใๆใกใพใ๏ผๆฑๆฅๆฌ๏ผ50 Hzใ่ฅฟๆฅๆฌ๏ผ60 Hz๏ผใใใผใใๅใฃใฆๆ็น้้ใ่ชฟในใใจใ้ๅใฎๆงๅญใๅใใใพใใ
5 ๆ็นใใจใซๅใฃใใใผใใฎ้๏ผ50 Hz ใชใ $\Delta t = 5/50 = 0.10$ sใ60 Hz ใชใ $\Delta t = 5/60 \fallingdotseq 0.083$ s
ๅใใผใใฎ้ทใ๏ผใใฎ้ใฎๅคไฝใ้ทใใ็ญๅทฎๆฐๅใชใ็ญๅ ้ๅบฆ้ๅใงใใ
5 ๆ็นใใจใซๅใฃใใใผใใฎ 1 ๅบ้ใใใใฎๆ้ $\Delta t$ใใฟใคใใผใฎๅจๆณขๆฐ๏ผ1 ็ง้ใฎๆ็นๆฐ๏ผใใ้็ฎใใใ
ใN ๆ็นใใ N ๅใฎ็นใชใฎใใN ๅใฎๅบ้ใชใฎใใงๆ้ใๅคใใใใ5 ๆ็นใใจใซๅใใใชใ้ๅธธใฏ 5 ๅบ้๏ผ็น 6 ๅใถใ๏ผใจ่ใใใๅ้กๅณใ่ฆใฆ็ขบ่ชใใใใ