testing tunnel diodes

[m3vuv]

Hi all,i need to test the tunnel diodes in my old tek scope,i know you cant test with a dmm,can anyone recomend a way to test them?,ie a schematic for a simple go/no go test jig,i have a scope and a sig gen,thanks in advance.

[David Hess]

Use your function generator to apply a sine or triangle wave through a resistor to the tunnel diode, and look for the negative-resistance switching with your oscilloscope.  Do not exceed the tunnel diode's voltage or current ratings.

https://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_other/Tunnel_Diode-Pulser/Tunnel_Diode_Pulser.html
https://w140.com/tekwiki/wiki/067-0681-01

[coppercone2]

and FYI I did probe tunnel diodes with a DMM before (in my 3310B repair), the voltage drop is low, but they did not break from a 34401A probing them in circuit. Just saying so you don't freak out if you test it accidentally, its not guaranteed to break, but you should take special precautions if you are soldering with them, like goot brand heat sink clips and ESD protection IMO.

To be honest I was not really comfortable or happy with the tunnel diode circuits until they were fully assembled back in their box, it s a pain in the ass to replace and people seem to have bad luck with them in general.

[RoGeorge]