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Fool'n around with DSO & AWG

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mawyatt:
Grabbed a 2N3904 from the junk pile and wondered if it was any good? Could have used a DMM or T7 Component Tester but that's no fun, so decided to see if the SDS2000X+ with an AWG could be easily "coached" into a Component Curve Tracer.

Set the AWG (SDG2042X) Channel 1 to provide the Sweep Voltage using a Trapezoidal Waveform with a DC Offset so the waveform is ~unipolar, this goes to DSO Ch1. AWG Channel 2 was setup with a Rising Stair-step waveform for the bias stepping. Used a 100 ohm current sense resistor for DSO Ch2 in the DUT emitter and a 1Meg base bias resistor to the AWG Ch2. AWG Ch1 was connected to the DUT collector. Here's the results with scope set to XY mode, it's noisy and made no attempt to reduce noise. Result was 2N3904 is fine :-+

#88 is 2N3904 with Vertical scale of 20mv/100 ohms, or 200uV/div

#91 is with higher collector sweep range

#90 was using a custom HV amplifier (we developed awhile back to augment the AWG, details somewhere here on EEVblog) connected to AWG to sweep the voltage higher to show beginning 2N3904 collector breakdown, note horizontal (DSO Ch1) scale factor.

Then we got a 3A 400V NPN and used a Juntek DPA1698 AWG Buffer Amp for more DUT current.

#92 is 3A NPN with 10 ohm emitter current sense R, so scale is 200mv/10 ohms or 20ma/div

#93 is with 1 ohm emitter resistor, scale is 200mv/1 or 200ma/div

Anyway, this was a little fun play'n around this afternoon.

Best,

RoGeorge:
He, he, nice weekend proj:  "Ad-hoc Curve Tracer!"  :-+

To see the reverse breakdown, I've used once a step-up transformer connected straight to the AWG's output (all passive, no amplifier).

P.S.
Please always add a hand-scribbled schematic with the setup, or else only those who already know will understand.

mawyatt:
Good name!!

Attached is the sketch and setup images.

Best,

tautech:
Thanks for sharing this with us Mike.  :-+

Can I ask if you have done this before with other DSO's or did that little voice inside your head tell ask you what happens if I do this ?

mawyatt:
Never tried this before with any DSO, back in our lab when I was working we had a proper Tektronix Curve Tracer, so no need to try.

Here's another trace with a Power NMOS device (18A 200V), works equally well as it should :)

Edit: And another of an IRF740 showing the NMOS Triode Region.

Gotta love just how versatile these DSOs are, they aren't just an oscilloscope but a very good Analog Data Acquisition system with almost unlimited flexibility. As 2N3055 mentioned over on the new Rigol HD thread, the ADC is only part of the overall System, the rest of the Data Acquisition needs to been done well and Siglent has certainly demonstrated such to us with the SDS2000X+ :-+

Best,

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