LECTURE: EKG Graph Paper

Overview
ECG paper: grid system

• 1 big box/square = 25 small boxes/squares
• 1 small box = 1 mm => 1 big box = 5 mm x 5 mm

Horizontal = time (s, ms)

• 1 mm (1 small box) = 0.04 s (40 ms)
• 5 mm (1 big box) = 0.2 s (200 ms)
• 5 big boxes = (0.2 s) x 5 = 1 s

Vertical = voltage (mm, mV)

• 1 mm (1 small box) = 0.1 mV
• 10 mm (2 big boxes) = 1 mV

Calibration:

• Standard: 10 mm (1 mV) high x 5 mm (0.2 s) wide; typical speed = 25 mm/s
• Half-standard: “stair-like” structure; ↓ voltage