Abstract: Methods and circuits to measure the speed of silicon test structures using direct current test equipment. Each test structure comprises an oscillator and a detector. Oscillations started by a direct current input signal are rectified by the detector into a direct current output signal. Start of oscillations cause a jump in the output signal and that point is correlated with the input signal strength which in turn is correlated to the speed of the test circuits. By knowing the speed of the test circuits the quality of the manufacturing process can be checked. Direct current greatly simplifies measurement so that 100% testing can be performed.