Are the Rhc and Rhp output resistors shown in the reference circuit in Appendix 5.2 of the user manual built into the instrument?
QAre the Rhc and Rhp output resistors shown in the reference circuit in Appendix 5.2 of the user manual built into the instrument?
Rhc and Rhp are not built into the LCR meter. Instead, they must be added outside the instrument. The 100 Ω resistance derives not from Rhc, but from the LCR meter’s internal output resistor.
Hioki sells a unit known as the 9269-10 for measuring DC bias in choke coils, but the coefficient is not publicly available. As described in the manual, failure to use a resistor that is large enough for the test sample’s impedance will result in a measurement error. Too small an Rhc value will cause too low a voltage to be applied to the sample, causing the SN ratio to deteriorate. Too small an Rhp value will reduce the voltage detection terminal’s input impedance, preventing the instrument from accurately detecting the voltage across the sample’s terminals.
By contrast, too large an Rhc or Rhp value will increase the time constant with the capacitor that is inserted in series with the measurement terminals, increasing the DC bias measurement stabilization time.
These phenomena vary with the capacitance of the capacitor being measured and the measurement frequency. Hioki’s 9269-10 is designed to take this type of phenomena into account.