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Test Equipment / Re: Siglent SSA 3021X... Ooops
« Last post by Joel_l on Today at 12:42:49 pm »This is helpful, thank you! Guess I'm not the only one.
Thanks
Joel
Thanks
Joel
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Beginners / Re: LM324 Power Supply with variable voltage and current
« Last post by xavier60 on Today at 12:37:39 pm »The tap changer could be powered from the same supply as the LM723 if the tap changer is modified to input negative sensing voltage.Initial thoughts are, the fans only can be powered from the 2x15Vac transformer.
The tap changer might be able to be powered from the 2x12Vac transformer with modifications so that it can accept negative sensing input voltage. Because the DVM can only measure positive voltage, it needs to be powered WRT the PSU's negative output. So the unmodified tap changer might as well be powered from the same supply.
Keep in mind that ground on a Harrison PSU is the positive output.
Can you please be more explicit ? Are you trying to explain that the tap changer could be powered if I modify the schematic ? Regarding the DVM, I didn't understood.
But there is no point because the DVM can only accept positive sensing input voltage so needs to be powered WRT the PSU's negative output terminal and the unmodified tap changer can also be powered from the same supply as the DVM.
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Beginners / Re: Quickly Triggering Sensors - need an oscilloscope? what specs? (AU)
« Last post by Aldo22 on Today at 12:37:06 pm »Oscilloscopes are for displaying signal waveforms, not creating them.
Basically yes, but the Hantek mentioned has a built-in signal generator (AWG).
This can be used to generate pulses, but not patterns (except perhaps within limits with an arbitrary waveform).
I don't quite understand the question and am therefore not sure whether he needs an oscilloscope at all.
The solution with the Arduino seems plausible.
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Projects, Designs, and Technical Stuff / Re: Opamps - Die pictures
« Last post by Noopy on Today at 12:36:56 pm »They describe it as "chopper stabilized" in the datasheet. If you think about it, the part S1, gm1, gm2, S2 is a chopper amplifier: S1 chops the differential input voltage into a square wave, the linear transistors amplify the square wave, and S2 demodulates it back into DC by sampling the peaks. To avoid differential subtraction of peaks and valleys at this point, gm3 works as a DC servo of sorts and ensures that the valleys are fixed near some internal "ground" potential.
The output of the chopper feeds gm4 and gm5, which provide additional gain. And the whole chopper is bypassed at frequencies near the chopping frequency and above in order to reduce aliasing artifacts and achieve GBW much higher than the chopping frequency.
Of course the "auto zero" explanation about gm3 canceling gm1 offset voltage and a bunch of sample-and-hold circuits making it all work is valid too. I'm not sure what the difference between "chopper stabilized" and "auto zero" is supposed to be, and if there is any real difference at all. Maybe it's only marketing talk.
I have read some articles and it seems that (today) it is common sense that "Auto Zero" is used for sampling circuits which meassure the offset and subtract it from the amplified signal. "Chopper" is used for for circuits that modulate and demodulate the signal and so loose the offset on the way. But the naming is mixed up a lot...
You are right, the sampling circuit is somehow a modulation too but in my view it´s a lot more a sampling thing.
"Stabilized" (chopper or auto-zero) means that there is a high frequency path parallel (at least that is what the articles said I have read).
It's probably same thing as with MCP6024: two dual dice can be installed together to realize a quad. The top die gets its V+ in bottom left and V- in bottom right. The bottom die is rotated 180° so its supply connections are swapped.
There are three unused bondpads in the lower area. These are additional options for connecting the supply potentials.
I suppose it works out cheaper than designing a quad die and disabling half of it for the dual
A good explanation!
The circuit corresponds to the block diagram in the LTC1052 datasheet. The datasheet states that the amplification factors of the amplifiers gm1 and gm6 must be as equal as possible for proper function. Furthermore, these are the amplifier stages with the high amplification factors. Accordingly, these two sections are relatively large and have the same structure.These things look like ordinary PMOS differential pairs with PMOS current sources in the middle between gm1 and gm6 and NMOS current mirrors.
Hmm, how far are you from a complete transistor level schematic of this opamp?
The circuit is not very complex and the complete schematic would be near but I somehow don´t like MOSFETs...
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Beginners / Re: Where to get datasheets of this part
« Last post by Terry Bites on Today at 12:34:22 pm »Try a vendor of the ic.
eg www.sierraic.com
Search for the ic and use the query box to get a datasheet.
eg www.sierraic.com
Search for the ic and use the query box to get a datasheet.
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Mechanical & Automation Engineering / Re: Repurposing PVC Pipe for DIY Projects
« Last post by xrunner on Today at 12:30:41 pm »Why do you think that builder is using it? Just curious your thoughts on it. He (or she) doesn't seem like a person to make a mistake like that.The builder is using CA glue. What's wrong with what he chose, seems to know what he's doing. You can use SCIGrip 16 if you don't want to use that.
CA glue is a bad choice for pvc
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Test Equipment / Cheap oscilloscope for checking mains power quality? Also logging equipment.
« Last post by mrsparkle on Today at 12:29:44 pm »Hello,
I am a residential electrician that occasionally has to troubleshoot issues such as LED flicker, GFI nuisance trips, and well that's about it. I am looking for a very basic oscilloscope or similar device that I can connect to the lines and check for noise / power quality issues. Mostly just to verify that X is the culprit, whether X is an ev charger or dirty power from the transformer.
As such, I do not want to spend a lot, and I have a fairly limited usage, only to be able to check for a malformed voltage or current waveform at 120/240V. What's a good selection for me? How cheap can I go, and what are the minimal specs I should look for?
Also, at times I may need to respond to an intermittent issue and attach a data logger inside a panel for a day or two that can pick up on rapid spikes or sags. Again, I would use this tool rarely and don't want to spend a lot. I know there are higher end loggers like Flukes, over $1k, which is more for industrial use, but its not nearly so critical to my job. Again, what would be minimum specs and price point for that?
Thanks
I am a residential electrician that occasionally has to troubleshoot issues such as LED flicker, GFI nuisance trips, and well that's about it. I am looking for a very basic oscilloscope or similar device that I can connect to the lines and check for noise / power quality issues. Mostly just to verify that X is the culprit, whether X is an ev charger or dirty power from the transformer.
As such, I do not want to spend a lot, and I have a fairly limited usage, only to be able to check for a malformed voltage or current waveform at 120/240V. What's a good selection for me? How cheap can I go, and what are the minimal specs I should look for?
Also, at times I may need to respond to an intermittent issue and attach a data logger inside a panel for a day or two that can pick up on rapid spikes or sags. Again, I would use this tool rarely and don't want to spend a lot. I know there are higher end loggers like Flukes, over $1k, which is more for industrial use, but its not nearly so critical to my job. Again, what would be minimum specs and price point for that?
Thanks
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Mechanical & Automation Engineering / Re: Repurposing PVC Pipe for DIY Projects
« Last post by langwadt on Today at 12:23:03 pm »The builder is using CA glue. What's wrong with what he chose, seems to know what he's doing. You can use SCIGrip 16 if you don't want to use that.
CA glue is a bad choice for pvc
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Beginners / Re: Blocking Phantom Power 48V from Audio output
« Last post by Terry Bites on Today at 12:22:26 pm »Have a good read.
See page 11.
See page 11.
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Beginners / Re: Comparator circuit seems to be oscillating (well, pulsing, really). Solutions?
« Last post by Terry Bites on Today at 12:19:50 pm »How about an actual schematic instead of vague blurb?