Question 4
5 pts
A differential amplifier is used to record the leads of the frontal ECG, as shown in the
Einthoven's triangle below, by connecting its inputs to different combinations of
electrodes RA, LA, and LL. Assume the triangle is equilateral and the augmented
lead vectors (aVL, AVR, aVF) bisect the bipolar lead vectors (I, II, III).
RA -
AVR
AVL
aVF
+ LA
LL
III
+
Lead
vector
+
Lead
voltage
Which of the leads is obtained by connecting the non-inverting input to the differential
amplifier to LA, and the inverting input to RA?
Lead aVF
Lead I
Lead III
Lead II
Question 5
5 pts
For the setting in the previous question, which of the leads would be obtained by
connecting the non-inverting input of the differential amplifier to LL and the inverting
input to the midpoint of a voltage divider with two identical resistors to RA and LA?
Lead II
Lead aVF
Lead aVL
Lead aVR