| Electronics > Beginners |
| Scope and Pk-Pk Values 1x vs 10x |
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| Dreded:
so while I have a super noisy environment I think I was hitting the bandwidth of my scope probes(100Mhz probes on 200Mhz scope im sure you can guess why)... putting bandwidth down to 20Mhz solved the noise not matching at 10x issue...(both read ~160mV now) also solved my other mystery that started all this... here is a shot of my PSU output when drawing a sudden 240mA load..I am grabbing ground off an assertion level pin(that is always asserted at GND with a physical selector switch)(from VFD).. apparently bad idea... if I use the other GND pin thats always GND this doesnt happen :p Woops. image 27 = 1/100x of pulling power |
| TK:
Try AC coupled input. |
| tautech:
@ Dreded Any scope can show nice and not so nice squiggly lines but really they are meaningless unless the scope is set correctly to capture a real measurement. Simple features for you to practice with are Single, Trigger levels and AC coupling. Unless you are really switched on and doing this stuff all the time settings are likely to be incorrect. Capturing these for another thread yesterday took a few attempts to get something that looked reasonable and portrayed all the info intended. These are power ON shots of a PSU and ripple checks when driving a 24V 5W bulb that drew 170mA. Ripple and noise spec for this PSU is max 350uV so any mains ripple is very hard to identify. Single trigger AC coupling and Averaging Having the appropriate menu in the screenshot helps give the reader info to accept the sceenshot to see that something might be wrong and suggest more appropriate settings. Understand first what you are looking for instead of blindly accepting what's on the display helps immeasurably with scope use. In my early scope days my mentor said that before you even connect understand first what you are looking for and what should be there ! When it's not then ask yourself why.....so often it's user error. :) |
| Electro Fan:
--- Quote from: tautech on May 10, 2019, 09:57:11 pm ---@ Dreded Any scope can show nice and not so nice squiggly lines but really they are meaningless unless the scope is set correctly to capture a real measurement. Simple features for you to practice with are Single, Trigger levels and AC coupling. Unless you are really switched on and doing this stuff all the time settings are likely to be incorrect. Capturing these for another thread yesterday took a few attempts to get something that looked reasonable and portrayed all the info intended. These are power ON shots of a PSU and ripple checks when driving a 24V 5W bulb that drew 170mA. Ripple and noise spec for this PSU is max 350uV so any mains ripple is very hard to identify. Single trigger AC coupling and Averaging Having the appropriate menu in the screenshot helps give the reader info to accept the sceenshot to see that something might be wrong and suggest more appropriate settings. Understand first what you are looking for instead of blindly accepting what's on the display helps immeasurably with scope use. In my early scope days my mentor said that before you even connect understand first what you are looking for and what should be there ! When it's not then ask yourself why.....so often it's user error. :) --- End quote --- Really good post / advice tautech ! |
| tautech:
--- Quote from: Electro Fan on May 11, 2019, 07:12:25 am ---Really good post / advice tautech ! --- End quote --- Why thank you EF. :) Well I like to think I have a good handle on the basics but yesterday when delivering a 4 ch X-E to a customer his young EE kept showing me up ! :-[ But really it was great to see a young technician with such good understanding of the 1202X-E that he had been using for some 18 months and the guy was quite excited that his boss had bought him a 4ch X-E and all the additional advanced functionality they offer. Only a small company but doing some really nice power electronics development particularly with wireless power transmission. 6KW over 200mm distance is pretty impressive with a goal of reaching 10KW in the near future. :o They wanted to connect the 2 DSO's using Trig Out for timing correlation so to have a total of 6 channels to better observe their power switching behavior. Now they have a total of 3 Siglent DSO's and a Tek TDS2012C that is long retired to office not bench duties. |
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