Aspects of the present invention are generally directed to taking measurements in a hearing prosthesis. In an embodiment, a power circuit, which may be a switched mode power circuit, is shut down during performance of the measurements to reduce interference. Then, power capacitively stored by the power circuit is used to power the hearing prosthesis during performance of the measurements. In an embodiment, the power circuit increases its voltage just prior to performance of the measurements. This serves to increase the amount of energy capacitively stored by the power circuit and thus extends the period of time during which the measurements may be taken while the power circuit is shut off.