Tunnel diodes: Difference between revisions

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 == Testing a Tunnel Diode ==
-Before concluding that a tunnel diode is bad, it is important to be sure that it has been measured correctly.  A high resistance reading on a DMM indicates that the diode is bad.  A low resistance on a DMM and a low voltage on a diode tester are both normal when measuring a tunnel diode.  A more thorough test of a tunnel diode is to drive it through a resistor with a ramp voltage source while observing the voltage across the tunnel diode.  The resistor should be calculated so that the peak current just exceeds the peak current that the tunnel diode is rated for.  Of course if a curve tracer is available, it is great for measuring the I-V curve of the diode (note the negative-resistance may not show).
+Before concluding that a tunnel diode is bad, it is important to be sure that it has been measured correctly.  A high resistance reading on a DMM indicates that the diode is bad.  A low resistance on a DMM and a low voltage on a diode tester are both normal when measuring a tunnel diode.  A more thorough test of a tunnel diode is to drive it through a resistor with a ramp voltage source while observing the voltage across the tunnel diode.  The resistor should be calculated so that the peak current just exceeds the peak current that the tunnel diode is rated for.  Of course if a curve tracer is available, it is great for measuring the I-V curve of the diode (note the negative-resistance part of the curve may not show due to the fast transit).
 A short article in [[Media:Service Scope 49 Apr 1968.pdf | Service Scope 49, April 1968]] describes a quick checking setup that approximates a curve tracer using the scope's X sawtooth output (see in photo section below).