An electrical circuit testing assembly that includes a mechanical reference that is relatively stationary as compared to a circuit under test. The stabilizer can be either titanium dioxide or aluminum dioxide. The conveying member enters the liquid reservoir while moving along the return route such that the chips adhered to the conveying member due to an oil component are separated in liquid in the liquid reservoir. The collectors of the first and second transistors are connected to the positive output terminal respectively via a second resistor and a buzzer. In this manner, the effect of quantization noise on the coefficients Cj can be reduced.