Hi,
I've been trying to measure several characteristics of an NMOS without success. I need to know how to use a curve tracer or o-scope (using electronics workbench and the real equipment) to make the following measurements: I-V family
Threshold
Transconductance curve
Pinch off voltage
Gm(gain)

I also need to obtain the following measurements using a BJT: Diode curve, Base turn on voltage, I-V characteristics, early voltage and beta(gain).

I'm really confused about how to do this, I believe in each case i'm supposed to connect the transistor in series with a resistor and then take the readings but i'm not getting any results. I'm not really sure how to set up the circuit and equipment to get these readings. Someone please help!

 

If you don't have a manual to follow, try the Wikipedia article and it's links - http://en.wikipedia.org/wiki/Semiconductor_curve_tracer. There are quite a few hits on Google, too.

 

Thanks a lot for the link. Please could you show me the circuit configuration needed for the extraction of NMOS parameters? I have tried several configurations (I've also searched the web for hours) but all I keep getting is an overload indication on the power source.

 

I've not used such a device in the last 20 years. My experience was all in BJT stuff.

Remember that NMOS is voltage rather than current controlled, and that the gate voltage should never go higher than 10 volts relative to the source. These are not power devices, so use a realistic voltage and resistor on the drain.

 

Is your curve tracer a Tek? Which model?

I'll try to dig up my notes on FET and BJT parameters extractions, it had been 13 years since I did my last characterisations so I don't remember all the details. However, I remember I didn't use any series resistor at all. The tracer limits the current (or voltage) depending on the maximum power setting, and keeps the DUT from overheating through pulse measurements (usually 300us or 80us pulses).