Posted: 8/25/2006 1:13:40 AM EDT
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I just rescued an old oscilliscope from the junk heap -- all it needed was a fuse -- and I've no idea what it does or how it does it. I mean, I've seen them in use and I know that this one was used to calibrate Commodore 64 disk drives, but how do I get it to display more than just an illuminated dot or a flat line? The inputs appear to be coaxial BIN types... are there standard connector sets? Obviously I'm not going top be putting it to any practical use, I just want to make those cool wavy lines. Do I need to input a real device or will dicking around with the connectors accomplish this? I've been to The Virtual Oscilliscope and it's fun to play with but it doesn't help with what I want to do (which is essentially nothing). I apologize in advance for wasting your time with this foolishness. |
| You need to apply some (low!) voltage to those BNC connectors. If you connect an AC signal you'll get a sine wave on the screen. You could also try plugging in a microphone. If you connect an AC signal to both inputs and turn off the timebase you can get these www.coolmath.com/coolthings/lissajous/index.html |
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There's an X-Y axis on the o-scope. The X axis usually measures time. The Y-axis measures amplitude. So you set the O-scope for, say, a scan frequency of 1000 Hz (1000 cycles per second). If you have a signal that is exactly 1000 Hz then you will see a perfect sine wave on the scope. Usually they have an adjustment knowb so you can raise or lower the scan frequency. And that just about exhausts my knowledge about them. |
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The easy answer is that they display voltage over time . Basically there are 8 vertical ( Top to Bottom ) divisions that are used to read the voltage . The 10 horizontal ( Left to Right ) divisions are for the time . Now say you wanted to view your house voltage . If you set the voltage scale to 20v per div and the time to 10ms per div . What you should see on the screen is a sine wave that roughly 6 divisions high and have 6 even peaks across the screen . The reason you see a wave 6 div tall is because 120v will take up 6 divs at 20v per. The reason you see 6 peaks is because you AC house voltage should be 60 hz or 60 cycles per second . So , 10 ms per div will display 100ms or 1/10th of a second on the screen , and 1/10th of 60 is 6 . That's about as simple as I can put it , without boring you to sleep 
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An oscillascope measures and displays voltage in time domain, that is voltage vs. time. You can also measure current vs. time. The connectors on the O-Scope are BNC plugs. You will need to buy a set of probes. The probes have a tip with a point and a return clip on them, sometimes they have a little clip that slips over the point to allow you to hook to wires and probe circuits. The probes will also attenuate, typically they divide the voltage by 10. You will want to get a manual for your scope. You need to know the max voltage the inputs can handle. So you do not burn out the front end by attempting to apply too high a voltage. You will also want to know the Bandwidth of your scope, this will be the limit as to what frequency of signal you can see. You will not be able to measure anything other than a sine wave at the highest bandwidth your scope is rated for, the frequency components of other waveforms will be over the bandwidth of your scope. That is if you try to measure a 10Mhz square wave and your scopes bandwidth is 10Mhz your signal will be verry distorted. Here is a link to the wikipedia article about O-Scopes Wiki Oscope You will also need to know the bandwidth to know which probes you should buy, no need in getting 100Mhz probes with a 10Mhz scope. You can get scope probes from Digi Key . Just do a search for Scope Probes. After you get some probes you need to get some resistors, capacitors, a breadboard, a wall wart power supply and a 555 timer. They you can make a cheesy little function generator. You can get the schematics and theory behind it in one of those Radio Shack project books. I would buy components and such from Digi Key, just get the project book from Radio Shack. RS is real expensive now adays. |
