Archive for May, 2011

Tektronix 577 curve tracer and 2SK363BL 2SK369BL Yfs (gain) measurement

Tuesday, May 10th, 2011

I owned this equipment for few years and got that from ebay Singapore for less than US$500.  The equipment label indicated that this machine was from AMD Singapore lab.  The condition is excellent as it was seldom used in a smoke free environment.  In fact, I want to own a curve tracer long ago because my first job is using Tektronix 576 for discrete part quality control.  Tek 577 fit to my needs for its size, weight, price and higher supply voltages till 1600V!


Here I use 577 to demo the measurement of jfets 2SK363BL (or 2SK369BL) that I am still selling right now.  The horizontal is 5v/div and thus 5 division is about 25V to the middle of the screen.  The vertical scale is 2mA/div.  Thus you can see the idss value by multiple the div to 2mA easily.  In my experience, due to its scale is on the screen with 0.2div resolution, thus the accuracy of the measurement is about 0.2/8 (max number of division) = 2.5%.  The top line is Idss, the line below top line is Idss at – 1 div or -0.1V and so on…  From the measurement, the Yfs is more than 50mS at about 8mA and this show that the jfet is well within specification.


If you observe the curve carefully, and calculate the Yfs using the -0.1V and -0.2V line, you will get a lower Yfs.  That means the Yfs decrease with working current (or bias point).


Another idea is use this machine to measurement vacumn tube (valve) but a fixture with safety precautions must be built as the it has very high voltage and power up to 100W!!! Take you own risk as I am not liable for that!