What unit is considered a measure of frequency in electrical stimulation?

The unit that is considered a measure of frequency in electrical stimulation is Hertz. Hertz (Hz) defines the number of cycles per second in a periodic wave. In the context of electrical stimulation, it refers to the frequency of the electrical impulses being delivered to the tissues. For instance, a frequency of 10 Hz means that there are 10 cycles of stimulation occurring in one second.

When considering the other options, microseconds are a unit of time that can measure the duration of an individual electrical pulse but do not indicate frequency. Amperes measure the strength of the electric current, representing how much charge is flowing through a circuit over time, while volts measure the potential difference in an electrical circuit. Neither of these units relates specifically to the concept of frequency, which is why Hertz is the correct choice.