3-3. MEASUREMENT PARAMETERS
The 4278A's measurement parameters and their relationships are described in the following
paragraph.
3-3-1. PARAMETERS
The 4278A measures parallel capacitance Cp or series capacitance Cs, and one of the fol-
lowing parameters: Dissipation Factor D, Quality Factor 0, Conductance G In parallel with
Cp, and Equivalent Series Resistance Rs in series with Cs. The measurement parameter
combinations which can be selected are Cp-D, Cp-Q, Cp-G, Cs-D, Cs-Q, and Cs-Rs.
NOTE
The 4278A displays equivalent series resistance as Rs.
3-3-2. PARAMETER RELATIONSHIPS
D and Q are not dependent on the equivalent circuit model, so D in Cp-D and Cs-D are
equal, and 0 in Cp-Q and Cs-Q are equal. The following equations show the relationship
between Cp and Cs, and between G and Rs. Cp and Cs are equal for the ideal capacitor,
where D=0. Cs will be greater than Cp if D is greater than 1. Figure 3-1 shows the relation-
ships among measurement parameters.
Cs = (D2 + 1)Cp
1/ESR = ((l/D2) + 1)G
Cp
Cs ESR
0-1
Y = G jwCp Z = ESA j(1/(wCs))
D = G/(wCp) D = ESRwCs
Q = 1/D ©=1/D
YZ = 1
Figure 3-1. Measurement Parameter Relationships
3-4
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