Message	Date	From	Subject
14334	2017-09-19 08:12:15	ab7vf	Curve Tracer
So I'm considering building a curve tracer .. What in (anyone's) opinion is a "good" range for the base step current/ gate step voltages ..Small signal npn/pnp ..njfet mosfets Jim
14335	2017-09-19 09:52:58	chuck adams	Re: Curve Tracer
I use You can set the steps and ranges and you can save the data in ASCII to your computer for plotting and analysis. I use gnuplot to generate curves. I can come up with some demos, if you like.... chuck, k7qo
14336	2017-09-19 14:22:44	Mike	Re: Curve Tracer
Jim: One of the on-line homebrew designs that I think might (at least partially) meet your needs is the design provided in "Electronics World" magazine for August 1971. This is available on-line (a google search on "Electronics World Magazine Archive" should provide a link). This design provides for base/gate drive steps of 2 uA to 1 mA/step for bipolars and 0.2 V to 1.0 V/step for JFET's. Although I don't think it directly addresses testing of MOSFET's. And this design uses 2n1671 unijunction transistors; I think the unijunction transistors could be replaced with dual bipolar arrangements per Solid State Design for the Radio Amateur pages 173-174. I can provide a list of other on-line resources for homebrew curve tracer designs if desired. 73 Mike Dinolfo N4MWP
14337	2017-09-19 17:56:23	jim	Re: Curve Tracer
Thanks Chuck and Mike for the replies I've got an op-amp based design (my first semi-original opamp effort) that I've glopped together as a first try .. It works, just trying to decide how many ranges and values. I'm mostly hardware hacking and staying away from software solutions "americanradiohistory.com" has almost all the magazines for perusal and download. I've found that the ujt based ones are too tweaky for my taste More to come as the rainy season hits Thanks again, Jim
14338	2017-09-20 00:21:53	chuck adams	Re: Curve Tracer
Jim, Good luck on the project. I got the Peak critter and I really love it. I realize it isn't for every one. ciao, chuck, k7qo
14395	2017-10-20 16:14:29	neiperalta	Re: Curve Tracer
Is there any missing connection in the Electronics Now schematic? Where does the emioter current flow to the collector power supply? 73 - LU5DNM
14396	2017-10-20 20:56:28	jim	Re: Curve Tracer

14397	2017-10-21 09:11:05	Norberto Modanesi	Re: Curve Tracer
Schematic you have mentioned in Electronics World. August 1971
14398	2017-10-21 21:45:15	jim	Re: Curve Tracer

14399	2017-10-22 10:22:48	Norberto Modanesi	Re: Curve Tracer
Yes. That is. 73
14400	2017-10-22 16:27:54	Jim Strohm	Re: Curve Tracer
Any chance that somebody can post that article to this group's file section along with a corrected schematic? 73 Jim N6OTQ
14401	2017-10-22 18:13:53	K5ESS	Re: Curve Tracer
Find it here; http://www.ka-electronics.com/images/pdf/Transistor_and_FET_Curve_Tracer_Daniel_Metzger_Electronics_World_August_1971.pdf Mike K5ESS
14402	2017-10-22 23:02:08	jim	Re: Curve Tracer

14407	2017-10-23 10:00:58	Norberto Modanesi	Re: Curve Tracer
I think there is another mistake in the schematic. How the Ib polarity is changed when changing NPN/PNP? LU5DNM De: emrfd@yahoogroups.com [mailto:emrfd@yahoogroups.com] Enviado el: domingo, 22 de octubre de 2017 10:14 p.m. Para: emrfd@yahoogroups.com Asunto: RE: [emrfd] Curve Tracer Find it here; http://www.ka-electronics.com/images/pdf/Transistor_and_FET_Curve_Tracer_Daniel_Metzger_Electronics_World_August_1971.pdf Mike K5ESS
14409	2017-10-23 22:01:21	jim	Re: Curve Tracer

14411	2017-10-24 21:56:18	Jim Strohm	Re: Curve Tracer
Looks to me like the two unobtainium unijunction transistors serving as relaxation oscillators could be replaced by NE555 or equivalent without too much difficulty. And ... what were the corrections again? I haven't really been following this thread carefully. 73 Jim N6OTQ
14414	2017-10-26 00:54:40	gi0gdp	Re: Curve Tracer
As a side to this i have a very similar but simpler curve tracer from 1970 something that i built. It never really had a job until about 1985 when alot of surplus RF devices appeared here and whilst they often where quoted as "25 watt FM" devices nobody had a clue as to what sort of Vce they had. Well the tracer sure shows it when at the end of the trace it goes vertical. Best of all calibration was dead easy you just got say a MRF247 and looked to see the point at the end of the constant current line at which it went vertical. Because it was all 50 Hz stuff there was no permanent damage. cheers Geoff GI0GDP Basically you could easily distinguish 28v devices from 13.8v ones
14418	2017-10-27 10:49:36	ab7vf	Re: Curve Tracer
Hello all For your amusement/consideration, I posted a circuit diagram for collector ramp/base step generation in folder "curve tracer" based on op-amps No unobtainum ujt's or that cruft ..I used lm158's cause thats what I had ..lm1458 did not work in the step-generator portion Jim

Message

Date

From

Subject

14334

2017-09-19 08:12:15

ab7vf

Curve Tracer

So

I'm considering building a curve tracer .. What in (anyone's) opinion is a "good" range for the base step
current/ gate step voltages ..Small signal npn/pnp ..njfet mosfets

Jim

14335

2017-09-19 09:52:58

chuck adams

Re: Curve Tracer

I use

You can set the steps and ranges and you can save the
data in ASCII to your computer for plotting and analysis.

I use gnuplot to generate curves. I can come up with some
demos, if you like....

chuck, k7qo

14336

2017-09-19 14:22:44

Mike

Re: Curve Tracer

Jim:

One of the on-line homebrew designs that I think might (at least
partially) meet your needs is the design provided in "Electronics World"
magazine for August 1971. This is available on-line (a google search on
"Electronics World Magazine Archive" should provide a link). This
design provides for base/gate drive steps of 2 uA to 1 mA/step for
bipolars and 0.2 V to 1.0 V/step for JFET's. Although I don't think it
directly addresses testing of MOSFET's. And this design uses 2n1671
unijunction transistors; I think the unijunction transistors could be
replaced with dual bipolar arrangements per Solid State Design for the
Radio Amateur pages 173-174.

I can provide a list of other on-line resources for homebrew curve
tracer designs if desired.

73
Mike Dinolfo N4MWP

14337

2017-09-19 17:56:23

jim

Re: Curve Tracer

Thanks Chuck and Mike for the replies

I've got an op-amp based design (my first semi-original opamp effort) that I've glopped together as a first try .. It works, just trying to decide

how many ranges and values.

I'm mostly hardware hacking and staying away from software solutions

"americanradiohistory.com" has almost all the magazines for perusal and download.

I've found that the ujt based ones are too tweaky for my taste

More to come as the rainy season hits

Thanks again, Jim

14338

2017-09-20 00:21:53

chuck adams

Re: Curve Tracer

Jim,

Good luck on the project. I got the Peak critter and I really love it.
I realize it isn't for every one.

ciao,

chuck, k7qo

14395

2017-10-20 16:14:29

neiperalta

Re: Curve Tracer

Is there any missing connection in the Electronics Now schematic?

Where does the emioter current flow to the collector power supply?

73 - LU5DNM

14396

2017-10-20 20:56:28

jim

Re: Curve Tracer

14397

2017-10-21 09:11:05

Norberto Modanesi

Re: Curve Tracer

Schematic you have mentioned in Electronics World. August 1971

14398

2017-10-21 21:45:15

jim

Re: Curve Tracer

14399

2017-10-22 10:22:48

Norberto Modanesi

Re: Curve Tracer

Yes. That is.

14400

2017-10-22 16:27:54

Jim Strohm

Re: Curve Tracer

Any chance that somebody can post that article to this group's file section along with a corrected schematic?

73

Jim N6OTQ

14401

2017-10-22 18:13:53

K5ESS

Re: Curve Tracer

Find it here;

http://www.ka-electronics.com/images/pdf/Transistor_and_FET_Curve_Tracer_Daniel_Metzger_Electronics_World_August_1971.pdf

Mike

K5ESS

14402

2017-10-22 23:02:08

jim

Re: Curve Tracer

14407

2017-10-23 10:00:58

Norberto Modanesi

Re: Curve Tracer

I think there is another mistake in the schematic. How the Ib polarity is changed when changing NPN/PNP?

LU5DNM

De: emrfd@yahoogroups.com [mailto:emrfd@yahoogroups.com]
Enviado el: domingo, 22 de octubre de 2017 10:14 p.m.
Para: emrfd@yahoogroups.com
Asunto: RE: [emrfd] Curve Tracer

Find it here;

http://www.ka-electronics.com/images/pdf/Transistor_and_FET_Curve_Tracer_Daniel_Metzger_Electronics_World_August_1971.pdf

Mike

K5ESS

14409

2017-10-23 22:01:21

jim

Re: Curve Tracer

14411

2017-10-24 21:56:18

Jim Strohm

Re: Curve Tracer

Looks to me like the two unobtainium unijunction transistors serving as relaxation oscillators could be replaced by NE555 or equivalent without too much difficulty.

And ... what were the corrections again? I haven't really been following this thread carefully.

Jim N6OTQ

14414

2017-10-26 00:54:40

gi0gdp

Re: Curve Tracer

As a side to this i have a very similar but simpler curve tracer from 1970 something that i built.

It never really had a job until about 1985 when alot of surplus RF devices appeared here and whilst

they often where quoted as "25 watt FM" devices nobody had a clue as to what sort of Vce they had.

Well the tracer sure shows it when at the end of the trace it goes vertical. Best of all calibration was dead

easy you just got say a MRF247 and looked to see the point at the end of the constant current line at which it

went vertical. Because it was all 50 Hz stuff there was no permanent damage.

cheers

Geoff

GI0GDP

Basically you could easily distinguish 28v devices from 13.8v ones

14418

2017-10-27 10:49:36

ab7vf

Re: Curve Tracer

Hello all

For your amusement/consideration, I posted a circuit diagram for collector ramp/base step generation in folder "curve tracer" based on op-amps
No unobtainum ujt's or that cruft ..I used lm158's cause thats what I had ..lm1458 did not work in the step-generator portion

Jim