US 5,705,936 A · Method and apparatus for automatically testing semiconductor diodes

Abstract

A potable electronic test instrument is adapted for the automatic testing of semiconductor diodes regardless of the orientation of the diode relative to the test probes. The test instrument supplies an a.c. sine wave test voltage coupled to the test probes. The maximum negative voltage and the maximum positive voltage are measured and compared against a set of predetermined open and short circuit values to obtain a decision of open, short, or ok for each value. The combination of the two comparisons is used to determine the device status according to a decision criteria. The diode status is accordingly displayed on the graphical display of the test instrument, indicating the device is open, shorted, a diode with a forward orientation or a reverse orientation with respect to the test probes, or of an unknown type. The diode forward bias junction voltage is displayed regardless of its orientation.

Claims16

Dependent claims

A test instrument for testing semiconductor diodes, comprising:

(a) a pair of test probes for coupling across a device under test;
(b) a voltage source coupled to said pair of test probes in a known polarity to develop a test signal in a positive polarity and a negative polarity across said device under test;
(b) an analog to digital converter coupled to said voltage source for converting said test signal into measurement values according to said positive polarity and said negative polarity;
(c) a microprocessor coupled to said analog to digital converter to receive said measurement values and determine a device status from said measurement values and said known polarity of said pair of test probes, said device status comprising open circuit, short circuit, diode, and unknown;
and
(d) a display device coupled to said microprocessor for displaying said device status wherein if said device status is diode, displaying an orientation of said diode relative to said known polarity of said pair of test probes.

3 more elements

Dependencies are inferred from the claim text.

Method and apparatus for automatically testing semiconductor diodes

Life of this patent

Method and apparatus for automatically testing semiconductor diodes

Life of this patent

Abstract

Claims16