Transistor testing

[e_man]

I have a budget component tester that I purchased on the Zon.

I use it to determine and verify specs on transistors, JFETS and other components.

I occasionally get readings that don’t make sense to me.

The above photo shows the readings for a J201.

This photo shows the readings for another JFET (not a J201).

I’m confused by the readings.  Does this indicate that the JFET is defective?

Have any of you had these kinds of reading show up when testing a transistor or JFET?

Thanks for any help you can give.

[Barry]

The problem is likely with your tester.

I only recommend a PEAK Atlas at the very least.

If they are purchased from me I batch test all of my JFETs before selling them. In a quality tester mine will read correctly 100% of the time. Further, test mine in circuit and you will find it operates correctly.

Cheap testers are completely unreliable.

 

[Cybercow]

Those cheap Chinese testers don’t do JFETs well at all. The symmetrical nature of JFETs confuse them. As Barry points out, a Peak Atlas DCA75 is far more accurate and reliable. And even then the symmetrical nature of JFETs can confuse a DCA75.

[e_man]

Thanks for the info gentlemen.

I’ll be looking for a better tester.

Thanks again.

[Big O]

Ditto what Barry and Cybercrow wrote.  I first used a $20 tester off Amazon and got ballpark figures for transistor gains and leakages, but graduated to using a DCA55.  I still use the cheapie tester for double checking diode anode/cathode positions as they can be different from one Ge diode to another.  I also use it to quick check resistor and capacitor values, but that is pretty much it.  For semiconductors, you really need to use a Peak Atlas device.

[Author]

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