1.Latent period - A short measurable period of apparent inactivity between the point of stimulus & the point of skeletal muscle contraction.
2.Einthoven's triangle - The roots of both upper limbs & the left lower limb form a equilateral triangle.
3.Induction current - It is interesting to note that current is induced in secondary coil from the primary coil during the change(i.e when current starts flowing in primary coil & again when it stops )