Zen 9 LU1014 Vgs Test

[vdi_nenna]

I picked up a MasTech 30v/6a power supply to test the LU1014 jfets for the Zen 9/F3, and for other projects. For some reason, I can't get the power supply to work correctly. There are very few setting. I guess lab power supplies require particular adjustments? I always expected to be able to set a lab PS by dialing in the amps, better than 1 amp in this case, and 3v.

There's Constant Voltage, Constant Current, Protected Current Mode.
These are set by either setting the I or V dials to their max.

I set the PS to constant current by cranking up the current setting and setting the voltage to 3V. when connected to the test circuit, the PS meters read 5+ amps and .8 volts.

To test, I ran a blue LED that was set with a resistor for 24v. At 5v it started to light and gradually became brighter moving toward 24v. IT seems to work correctly.

Another thing I don't understand the outputs: Neg, Gnd and Pos.
I thought the Neg terminal was for Neg voltage. The manual says to connect the Neg and Pos teminals. How or when is the Gnd used?

Any experience with this type of lab power supply would be appreicated.

Thanks,

Vince

[vdi_nenna]

How or when is the Gnd used?

Saw a video on youtube.com The ground can be used if a -V/0/+V output is needed.
In this case two HY30006D PS would be needed. Mine is single output.

[vdi_nenna]

Ok. It's been figured out. Must have been a bad connection in the bread board. Used alligator clips in place of the breadboard. The voltage and current worked fine. Got readings of 1.13 and 1.12 Vgs.

Thanks for looking!

V~

[vdi_nenna]

The LU1014d gets warm fast with 1 amp running through it in this test.
The Vgs should be taken when the Jfet is at room temp. Is the final reading taken when the voltage settles or is the first reading after turn-on the correct Vgs? Does the gate to source voltage rise and come back down?

The first jfets tested climbed above the scale in the article.
See scale.

[vdi_nenna]

No one knows?