A normal electrocardiogram (ECG) has several distinct characters, including:

  1. P wave: Represents atrial depolarization, should be rounded and smooth, not exceeding 2.5mm in height or width.
  2. QRS complex: Represents ventricular depolarization, should be 80-100ms wide, and less than 5mm high.
  3. T wave: Represents ventricular repolarization, usually follows the QRS complex and has a different direction from the QRS.
  4. PR interval: Represents the time between P wave and QRS complex, should be between 120-200ms.
  5. ST segment: Represents the interval between the end of the QRS and the beginning of the T wave, should be flat or slightly upward sloping.
  6. QT interval: Represents the time from the start of the QRS complex to the end of the T wave, should be less than 440ms in men and 460ms in women.

Note: These characters can vary based on age, gender, and other factors, but the above values are typical for a normal ECG.