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DPRG: correction of 'nickel' advice

Subject: DPRG: correction of 'nickel' advice
From: Eric B. Olsen robojoc at worldnet.att.net
Date: Sat Jul 19 22:45:43 CDT 1997

Eric B. Olsen wrote:
> droid at bellatlantic.net wrote:
> >
> > I was just on teh flea market. I have buoght two Tectronix
> > oscilloscopes.These two are 5103N models and look pretty old...I
> > think that these are 2 channels ....I turned them both on but on one of
> > them in order to see the dot on one of them I had to press BEAM
> > FINDER...and as soon as I'm letting the button go, the dot on the screen
> > disappears...can you tell me what is wrong with it ?
> > Now ...this thing does not have a probe to it...I looked at the jack and
> > it seems to be using a coaxial cable ...I might be wrong...now, can I
> > make my own probe(that is to go to the Radio Shack and buy the connectors
> > and the coaxial caable...) or I should buy a new one...I have looked in
> > the JDR Microdevices and tehy have a probes like for $19.95...I just
> > don't know...
> >
> > Other than that I think I hmade a good deal...
> > In addition to this..for the same $10 I got a TRANSISTOR CURVE
> > TRACE...now I never heard of that so what the hell is it I have no
> > clue..I looked inside and noticed that it must be pretty old since it
> > uses the vacuum tubes....can anyone here help me or comment ?
> >
> > :)
> droid,
> A transistor curve checker is a device used to check the gains and other
> hybrid parameters of a transistor.  The most common measuerement is an
> "I-V" curve, ... i.e., the collector current versus the base-emitter
> voltage.  This curve will give generally demonstrate the transistors
> "turn-on" characteristics.
> Other types of measurements are usually supported as well.  Unlike a
> common oscilloscope, the curve tracer works using both X and Y
> deflection, thus, a two dimensional pattern is traced as opposed to a
> "sweep" pattern.  Curve tracing equipment was likely important in the
> older days when transistor based designs dominated the engineers
> notebook!  Today, simulation based design dominates both in the lab, and
> in the design environment.
> Your scope probes will cost more than your equipment, but are a bit
> simpler to use!.  Real scope probes generally employ 50 ohm or so
> termination, and thus, homemade ones may read 'double' voltages .. you
> may have to adjust for this factor.
> Eric Olsen
> Las Vegas, NV

The correct impedance of the scope probe is "1 Meg Ohm or so....", to
replace the phrase "50 Ohm or so ...", sorry!

Eric Olsen
Las Vegas, NV


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