SZK series impedance converter is one converter unit of SSZ-S series instruments. For voltage, it is high input impedance ≥1MΩ and low output impedance ≤1Ω which accept large impedance signal and output low-impedance signal. so it is used to the place where need reducing output impedance signal in DDZ－S series system. For current, the input impedance is 250Ω but the output is capable of driving 250 ~ 750Ω load. So it can be applied to the area where need to expand the carrying capacity in DDZ-S-based systems. In addition, SZK impedance converter is an input voltage (or current) signal output current (or voltage) signal models, it can be used in the occasions which require voltage / current converter, or current / voltage conversion.