A method includes, in at least one aspect, receiving a digital voltage signal representing a voltage supplied to a circuit having a load, identifying a first time stamp associated with a voltage value representing an extrema in the digital voltage signal, receiving a digital current signal representing a current drawn by the load in response to the supplied voltage, identifying a second time stamp associated with the digital current signal, the second time stamp being within a threshold time of the first time stamp, and identifying a current value associated with the second time stamp as the current drawn by the load.