A test circuit for a ring oscillator comprising a plurality of inverting stages includes a power supply, the power supply configured to provide a voltage to the plurality of inverting stages of the ring oscillator at a power output; and a power sensing resistor located between the power output of the power supply and direct current (DC) bias inputs of the inverting stages of the ring oscillator, wherein a signal from the power sensing resistor is configured to be monitored to determine a characteristic of the ring oscillator.