Help Me Understand my TC-1

[BuddytheReow]

Here is a 2n5457. I get that Id is drain current. What does Vg mean? Is this the pinch off voltage?

 

[Big Monk]

Here is a 2n5457. I get that Id is drain current. What does Vg mean? Is this the pinch off voltage?

They aren’t really suited for measuring JFETs in my experience.

 

[fig]

Here is a 2n5457. I get that Id is drain current. What does Vg mean? Is this the pinch off voltage?

Vg = [V]oltage measured @ [g]ate.
Vgs = [V]oltage measured between [g]ate and [s)ource.
Vgs-off or pinch = Voltage @ which the DUT shuts off.
Vgs-on or Vgs(TH) = Voltage @ which the DUT shuts on.

 

[Big Monk]

Vg = [V]oltage measured @ [g]ate.
Vgs = [V]oltage measured between [g]ate and source.
Vgs-off or pinch = Voltage @ which the DUT shuts off.
Vgs-on or Vgs(TH) = Voltage @ which the DUT shuts on.

Tim points out the fundamental issue with JFET testing and the TC-1: It doesn't give Vgs-off, which is the parameter most people are measuring and sorting for.

the R.G. JFET tester is the way to go. I have an old breadboard attached to a 1590DD baseplate that has an R.G. JFET and transistor tester permanently setup. My TC-1 gets used for Si sorting, rough sorting of Ge and as my main passive component tester.

 

[fig]

The DCA75 does all that but is overpriced (just my opinion). Like Derek said, a few common components and you have a reliable method. I'd suggest adding a ZIF (they're the bomb for this).

 

[BuddytheReow]

Tim points out the fundamental issue with JFET testing and the TC-1: It doesn't give Vgs-off, which is the parameter most people are measuring and sorting for.

the R.G. JFET tester is the way to go. I have an old breadboard attached to a 1590DD baseplate that has an R.G. JFET and transistor tester permanently setup. My TC-1 gets used for Si sorting, rough sorting of Ge and as my main passive component tester.

Do you mean this?

 

[fig]

Do you mean this?
View attachment 21828

That's the matcher, yes. I think I've got a spare pcb from OSHPark if you want it.

 

[BuddytheReow]

That's the matcher, yes. I think I've got a spare pcb from OSHPark if you want it.

If you've got an extra and willing to part with it, sure I'll take it.

 

[fig]

I'll do you one better; RTG and headed your way.

 

[BuddytheReow]

I'll do you one better; RTG and headed your way.

You are too kind fig!

 

[Stickman393]

The manual really oughta come with these things.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.circuitspecialists.com/content/430516/csi-tc1.pdf&ved=2ahUKEwjujqDfkb71AhXIIEQIHcJOCq8QFnoECAwQAQ&usg=AOvVaw1wdpfuVAceXihKeUQJuEoz

Mine had a battery that died after a month. I found that there's plenty of room for a larger pack inside, though. I slapped an 1100mah flat pack in there...lasts much longer per charge now.