Author Topic: Oscilloscope  (Read 13844 times)

MacGyver

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Re: Oscilloscope
« Reply #15 on: December 10, 2008, 08:56:56 PM »
I suggest you read up on the grounding and safety issues. Please be safe....

I still own a V-212. Bought it new 20+ years ago.
Not a bad little no frills 2-channel scope. I've put lotsa mileage on mine. If you have any specific questions about it let me know.

Here's the operators manual:
http://www.weirdstuffwemake.com/sweetwatergems/electronics/misc/Hitachi_V212_Operation_Manual.pdf

Steve

JKson (PS) 6/1 'roid & ST 7.5

lendusaquid

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Re: Oscilloscope
« Reply #16 on: December 11, 2008, 08:18:32 PM »
Thanks for all the links and the manual. Ive got a lot of reading to do now.I would like a step by step how to do it if possible to satisfy my lack of patience and curiosity,if possible.Ive also just been given an Avo 8 which looks nice enough to put on display.A local college is shutting down a department and throwing all this gear in a garbage skip.A mate of mine works at this college and is raiding the skip for anything he can find. Much happyness :D 

mkdutchman

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Re: Oscilloscope
« Reply #17 on: December 12, 2008, 01:55:04 PM »
.....throwing all this gear in a garbage skip.

And these guys are supposed to be teaching young folks?  :P That oughta be criminal.......what a waste.......

compig

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Re: Oscilloscope
« Reply #18 on: December 12, 2008, 02:41:46 PM »
Thanks for all the links and the manual. Ive got a lot of reading to do now.I would like a step by step how to do it if possible to satisfy my lack of patience and curiosity,if possible.Ive also just been given an Avo 8 which looks nice enough to put on display.A local college is shutting down a department and throwing all this gear in a garbage skip.A mate of mine works at this college and is raiding the skip for anything he can find. Much happyness :D 

Nice 1 !! Any nice variable DC lab power supplies going ??!!
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MacGyver

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Re: Oscilloscope
« Reply #19 on: December 13, 2008, 08:29:11 PM »
Thanks for all the links and the manual. Ive got a lot of reading to do now.I would like a step by step how to do it if possible to satisfy my lack of patience and curiosity,if possible.

OK, here's a quick run down on the controls on your V212. Maybe it'll help get you started where to set the knobs to look at the output of your generator. These descriptions are kind of "basic"  and geared towards looking at a120VAC and 50/60Hz generator output. Sorry if If I've made any errors. As always, the info in your Operators Manual is best.

I won't repeat the safety issues about grounding (or ungrounding) or using isolation xformers or whatever.   Please be careful is all....


Here we go...

ON/OFF button.  Pretty self explanatory.

Next down, there's a hole for trace rotation. You can stick a screwdriver in here and adjust the trace so that horizontal is correct.  Leave it alone for now.

INTENSITY.  How bright it is. (duh) Try and use the lowest comfortable brightness. Excess intensity for long periods of time can "burn" the phosphor on the screen and leave dark areas. Start about 1/2  way up and adjust to taste.

FOCUS. Once the scope is fully warmed up, adjust to get the narrowest, sharpest (least fuzzy) trace.

TIME/DIV.   This sets how long it takes the trace to sweep horizontally. The graticule on the V212 is 10 divisions wide and 8 divisions high, so if you set the Time/Div to 1mS, it will take 1millisecond to sweep across 1 division, and 10 milliseconds to sweep across the entire face. Since 50Hz equals 20mS per cycle, a Time/Div setting of 2mS would result in a 50Hz sinewave just filling the entire screen horizontally. A slower setting (5mS/Div) would show more complete cycles on the screen and a faster setting would stretch out the waveform to see less cycles but detail.  Start at about  5mS/Div and play from there.

VOLTS/DIV.  This sets the vertical amplitude... how many volts it takes to move the trace vertically.
   So, 120VAC(rms) = 170volts peak, or 340 volts peak to peak.  So with a setting of 50V/Div, a 120VAC(rms) [340Vp-p] sine wave would span nearly 7 vertical divisions. If you used a 10X scope probe, which divides the signal amplitude by 10, then you would use 5V/Div to get the same results.
Note that there are 2 Volt/Div knobs, one for each channel.

AC coupling switch. This 3 position switch has AC, GND, and DC settings.
On "DC", signals are shown "as is" and the scope can measure AC as well as DC signals.
On "AC", the signals are AC coupled, which means that any DC component is blocked. This is handy for looking at AC signals that ride on top of a DC level. Like looking at "noise" from the output of a car alternator, where there may be a few hundred millivolts of AC noise that rides on top of a 12 - 15VDC battery voltage.
For looking at the output of your AC generator, you can use either the AC or DC setting, since there should be no DC component to the signal.
"Ground". This simply grounds the scope input and allows no signal to pass. This is handy for momentarily killing the signal so you can set where the trace is (vertically) with no input.
There's one of these switches for each channel.

SWP VAR. The variable sweep knob allows you to fine tune the sweep rate and It's effect is similar to the "TIME/DIV" knob except that it''s infinitely variable instead of the finite (and accurate) steps of TIME/DIV.
Note that if SWP VAR is in any position except the far clockwise "cal" position, the actual TIME/DIV shown will not be accurate.

POSITION (vertical) Sets the vertical position of the trace. For measuring AC signals, centered vertically is usually best.

POSITION (horizontal) sets the horizontal position of the trace. Pulling the knob out expands the trace 10X. You'll mostly use with the knob pushed in. (normal position)

MODE has 5 positions... CH1, CH2, ALT, CHOP, ADD.
 If you only have 1 scope probe, then you will only need to use CH1 (or CH2 if you prefer). ALT, CHOP, ADD are for displaying signals from both channels (2 probes) at once.

INT TRIG  Internal triggering. Just leave it set to whichever input channel your iprobe is on (probably CH1)

LEVEL This sets up the trigger level. If you look at your signal on the scope and it appears to be "scrolling" horizontally, then you need to adjust the trigger level to "freeze" it in place. Once you've got the motion stopped, then you can fine tune the trigger level to set where in the cycle (what voltage level) the scope starts it's sweep from.  Play with it and see....

SOURCE (trigger)  Mostly just leave it set to "Int" for general work.

CAL 5V  This little post has a 5 volt peak to peak square wave on it. As I recall it's about 1Khz.. Connect your scope probe to it to verify vertical calibration.

Errr... I think that's about al the controls on the face that you need to think about to start with. You've got a link to the Operators Manual for "the bigger picture".
Let me know if you have any other questions about your V212

Steve

JKson (PS) 6/1 'roid & ST 7.5

lendusaquid

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Re: Oscilloscope
« Reply #20 on: December 13, 2008, 10:55:11 PM »
Thanks Steve thats just what i needed to get me started.Ill still gen up with the manual but what you have written has made things a lot clearer.
Compig
All i got given was some low voltage soldering iron supplies with some soldering irons.

jzeeff

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Re: Oscilloscope
« Reply #21 on: January 08, 2009, 04:13:59 AM »

I agree - ground the scope and plug into wall power but make sure the generator is not grounded.

Do most people ground their generators?   For small portables, I've never bothered with it.

An AC transformer to reduce the voltage should give you a good idea of what the waveform looks like.


TxBlacksmith

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Re: Oscilloscope
« Reply #22 on: March 03, 2016, 04:20:12 PM »
I stumbled onto these two scopes on craigslist, and bought both of them for only $15.00 yesterday.  I have had no luck
finding any manuals for them, I guess, do to their age.  Can anybody point me to O-scope 101 for dummys?
I have never used one in my life.  I just want to be able to use them to check my ST head when I get it up and running.

The older I get, the more stupid I tend to think I am!


t19

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Re: Oscilloscope
« Reply #23 on: March 03, 2016, 11:50:34 PM »
Good God I have not used one of those things in decades... 1989?
There is plenty of room for all of Gods creatures... right next to the mashed potatoes...

BruceM

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Re: Oscilloscope
« Reply #24 on: March 04, 2016, 12:28:30 AM »
For most basic work and troubleshooting, an hand held single channel digital 'scope is cheap and effective.  The ability to capture a waveform is VERY handy for slow speed signals or for non-repeating events, which an analog scope just can't show you.  That plus fitting in your tool box, portability and no AC needed is a huge plus.

Thob

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Re: Oscilloscope
« Reply #25 on: March 04, 2016, 02:11:21 AM »
Lots of good information right here in this thread - I will especially direct your attention to the safety information covered here.  Don't kill yourself or your generator!  Most scopes have the ground lead tied to the metal chassis - that can result in rather unpleasant things happening if you connect the ground lead to anything that isn't grounded.  There's also a couple of links in the 3rd post that still seem to work - I didn't check them for accuracy but just a quick look seemed like they explained things.

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TxBlacksmith

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Re: Oscilloscope
« Reply #26 on: March 05, 2016, 05:44:43 PM »
 ;D Thank you for the advice gentlemen.  I would like some suggestions as to a handheld digital yall would
recommend.  I guess it comes from being a reenactor, Blacksmith etc. , but I own more old school tools than modern
ones.  I have a soft spot for good old used tools that gets the best of me!  :o  My late Mother always told me I was
born into the wrong century...

BruceM

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Re: Oscilloscope
« Reply #27 on: March 05, 2016, 07:53:38 PM »
If you have a laptop and a small tool budget:
http://www.amazon.com/SainSmart-Portable-Handheld-Oscilloscope-Bandwidth/dp/B00FYGEFYM/ref=sr_1_2?ie=UTF8&qid=1457207292&sr=8-2&keywords=usb+oscilloscope

I prefer to use a stand alone unit.  Mine is an obsolete Velleman.  I think today I'd try out one of the SainSmart or similar units.
Velleman's scopes are decent and reliable also.


Thob

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Re: Oscilloscope
« Reply #28 on: March 07, 2016, 01:35:51 AM »
If you want to learn about oscilloscopes, one option is to get a small power transformer with a low voltage output - 6 or 12 volts works well and is "safe".  Connect the primary to insulated leads to the mains, and feed the secondary into the "vertical" input on your scope.  You should be able to play with the 'scopes you have and synchronize a nice sine wave on the display.  It will at least get you a feel for what you can see and how the various knobs work on the scope.

Have fun, stay safe!
Witte 98RC Gas burner - Kubota D600 w/ST7.5KW head.
I'm not afraid to take anything apart.
I am sometimes afraid I'm not going to get it back together.