Electronic component measurement apparatus
AssigneeHewlett-Packard Company
InventorsHeinz-Gunter Bach, Wolfgang Dressler
Life of this patent
Estimating the term…
Abstract
Apparatus for measuring the A.C. characteristics of a circuit element under test maintains a stable D.C. bias voltage across the component under test by sensing the difference between the output voltage of the D.C. bias voltage source and the voltage drop across the circuit element under test, to control the D.C. bias voltage applied and to compensate for variable voltage drops in the measurement circuit. The apparatus compensates both for the fixed resistance in the circuit and for the variable resistance due to changing the range resistor.
Claims2
Apparatus for measuring A.C. characteristics of a component to which superimposed A.C. signals and D.C. bias voltages are applied, in a measurement circuit having a variable range resistor, comprising:
- an A.C. signal source connected to the component under test for providing the A.C. signal across the component;
- a D.C. variable voltage source connected with the A.C. signal source for providing a selected D.C. bias voltage superimposed on the A.C. signal;
- means for detecting the D.C. voltage drop across the component under test;
- control means including an operational amplifier with high gain for comparing the D.C. voltage drop across the component under test with the output voltage of the D.C. variable voltage source to control the applied D.C. voltage to maintain the D.C. voltage drop across the component under test substantially equal to the output voltage of the D.C. variable voltage source;
- and
- means for measuring the A.C. characteristics of the component under test.
Dependencies are inferred from the claim text.