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Automatic Tunnel Diode Analyzer Disclosure Number: IPCOM000097447D
Original Publication Date: 1962-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 44K

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Bojman, W: AUTHOR


This analyzer precisely measures the D.C. characteristics of tunnel diodes.

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Automatic Tunnel Diode Analyzer

This analyzer precisely measures the D.C. characteristics of tunnel diodes.

Variable D.C. supply 20 is connected through load resistor 22 to tunnel diode 24 under test. Operational amplifier 25, connected in series with supply 20 and diode 24, delivers an output to servo amplifier 26 through a controlled switching device 28. Amplifier 26 controls servomotor 30 which adjusts the voltage of supply 20. Digital voltmeter 32 is connected to amplifier 25 through switch 34 to read the diode current and diode voltage. A small 60 cycle current is supplied through switches 36 and 38 to transformer 40. The secondary of 40 is coupled through resistor 42 as a second input to diode 24. An IBM card punch 44 controls switches 28, 34, 36 and 38 to record automatically the D.C. voltage and current of the diode under test.

When the system is turned on by closing switches 28, 36 and 38, the servo system adjusts the D.C. voltage to a value corresponding to peak current P (lower drawing) of the diode under test in the following manner. The injected A.C. current is superimposed on the D.C. voltage and provides an indication of the incremental conductance of the diode. When the diode conductance is zero, the peak current of the device under test is reached. The phase of the A.C. current changes on either side of the zero conductance point so that the servo system homes in on the peak value P. When the diode conductance is zero, the servo is disconnected b...