In some embodiments, a power extractor utilizes power transfer circuitry with analysis circuitry to detect a power slope and to control the magnitude of the current in response to the detected power slope. The power analysis circuitry may increase the current as long as the power slope shows an increase in power and may decrease the current as long as the power slope shows a decrease in power. The magnitude of the current is responsive to the duty cycle of the switching circuitry and to the detected power slope. Other embodiments are described and claimed.