What is the standard unit for the phase charge in electrical stimulation?

What is the standard unit for the phase charge in electrical stimulation?

• A. Coulomb
• B. Ampere
• C. Volt
• D. Ohm

Answer: (A)

Charge is the amount of electricity delivered in one stimulation phase. The standard SI unit for electric charge is the coulomb, defined as the amount of charge transferred by a current of one ampere in one second. In clinical practice for electrical stimulation, this is typically expressed in microcoulombs (µC) because the phase-delivered charges are small, with 1 µC equal to 10^-6 coulombs. The other quantities—ampere (current), volt (potential), and ohm (resistance)—describe different aspects of the system, not the total charge delivered. For example, delivering 1 mA for 1 ms gives Q = I × t = 0.001 A × 0.001 s = 1 × 10^-6 C, which is 1 µC. So the fundamental unit is the coulomb, with microcoulombs used for practical per-phase values.

Charge is the amount of electricity delivered in one stimulation phase. The standard SI unit for electric charge is the coulomb, defined as the amount of charge transferred by a current of one ampere in one second. In clinical practice for electrical stimulation, this is typically expressed in microcoulombs (µC) because the phase-delivered charges are small, with 1 µC equal to 10^-6 coulombs. The other quantities—ampere (current), volt (potential), and ohm (resistance)—describe different aspects of the system, not the total charge delivered. For example, delivering 1 mA for 1 ms gives Q = I × t = 0.001 A × 0.001 s = 1 × 10^-6 C, which is 1 µC. So the fundamental unit is the coulomb, with microcoulombs used for practical per-phase values.