To reduce the loop area and noisepick up, the GND lead of the scope probe is very next to the tip in the below probe:    I don’t have such probes and my scope probe GND leads are much longer alligator clips.  Does the type of probe in the photo have a name or is it homemade? And when is it used?
123440
Exactly what it says on the tin.    How is this pictured accessory called? The obvious place to look for a name would be the probe manual, but it looks like they decided to add the accessory to the package after making the manual, since it's not on the component list.
33757
How does a cap on a regulator output improve transient response? Is this cap not more appropriately drawn next to the load where it is not being defeated by intervening trace inductance? Or does this output cap serve a different purpose than the typical bypass caps seen on a digital IC power supply pin?        Edit: This has been flagged as a possible duplicate. While the answers may have some overlap, the titles of the three questions I asked are very specifically different questions. This should be evident upon reading the Titles.
11764
What would be the best method for making regularly spaced holes in a cylindrical mesh? Similar to the vent holes you'd see on gun barrels like these:       Without creating any n-gons, having good topology, and not excessively increasing the tri/polycount overall (this is for models that would potentially be used in a game). It would be good to know how to do this in a way that would work where the holes overlap on the x axis of the cylinder if you see what I mean, like the MG34 barrel, and where they don't, like the SMG barrel.
96979
On many boards I've seen, there are little copper dots used for the purpose of "Copper Thieving". They're small round copper dots connected to nothing and arranged in an array. Supposedly they're for balancing the copper on the boards to improve manufacturability, but no explanation I've heard has convinced me that they're needed or useful. What are they for and do they actually work?  Below is an example with squares.
96849
When I touch with my bare finger the oscilloscope probe I get a perfect sine ac wave 155V peak to peak!.  This is my first oscilloscope and I don't know if this is a normal glitch.  Do I have a faulty one?
28338
Is there a standard for the sizes of PCB traces?  That is are some 25 mil and others 10 mil or is can you choose your own?  I plan to run 400mA through some thicker traces, but less than 30mA for all other traces. About what size would I need?
82077
I keep hitting a wall on my projects where I can't really tell what's going on and decided I really need an oscilloscope to proceed intelligently.  I've got a Rigol DS1052E in the mail after a few recommendations.  I know the kinds of things I need to measure, but I want to make sure I don't blow it up the first day.  What kinds of tips do you guys have for effectively using a scope and avoiding damage to it while getting useful information out of things?
22926
On some PCB designs, specific traces are routed in curious ways. This probably has to do with high frequency design considerations and general signal behavior that I am not familiar with.  Let's take this PCB (somewhere from the web) as an example. It shows part of a PCIe card with SATA routing and DDR2 RAM:    I highlighted 4 areas that qualify as unusual trace layout (from my perspective).   What are those shapes supposed to achieve? How do designers come up with what pattern is required? Another example of wave shaped, antenna like routing. This is fairly rare. But obviously the designer deliberately avoided 45° traces. Why? Curves again and a single "pulse" within the trace. How can this have any significant effect?   So what are the use cases and benefits of this techniques?   I want to be able to take those into consideration when doing future PCB designs.
19331
Having no prior experience with scopes, it seems strange to me that when the probe is not measuring anything (~ not connected to a circuit) it measures a small 50Hz (~ my mains are running at 230V 50Hz) signal instead of some random noise. Is this normal behaviour (my scope is a Rigol DS1052E)?
85610
I discovered that my soldering iron has voltage at the tip and it seems to increase the hotter the iron gets. Should I be worried? I've been trying to repair an old CRT monitor and I'm worried the issues I've been having are due to this cheap iron damaging something.  How to meassure voltage of an soldering iron tip? Where to put probes?
93688
I am building a mini pinball machine, which is about 10x22cm.  To drive the flippers I plan to use this 5v mini push/pull solenoid:  , along with momentary SPST buttons and a 5V 2A wall power adapter.  Those are the only electronic components in the machine. I am not using an Arduino or any other controller.  In this scenario, is it advisable to use a diode (or any other components) to protect the power supply?  If diodes or other components are advisable, I will be grateful if you could explain at a very basic level why they are needed and where they should be inserted into the circuit.  The schematic below is pretty much the current extent of my electronics knowledge.  I am interested in expanding my knowledge but find many of the technical terms used on this site overwhelming.  Here is the circuit that I have so far:
79435
Bought some "music speaker" thingies, some with bluetooth and some without. They are cheap, for sure, about 3 or 4 euro's. With some capacitor tweaks, they seem to be very plausibel to use (why is the output on these cheap things always tiny and limited?).  On these devices they use a very tiny, nice and bright display, with 7 legs, charlieplexed I suppose (wiggle it to see any screen update), 35 segments. Cannot read the number on the used chip (it's from JL), very hard to recognize (even when using a microscope) and the display doesn't have any partnumber on it either, however, these seem to be identical except the face plate on these components.   The displays are very interesting, just 7 pins to do the display job, in just one package. I want to buy these things (cannot find it, doesn't know the name and cannot find a datasheet either).   Next thing I want to do is to interface with these devices by reading the display (with a MCU for example) so I am able to read the state of the device and what it is doing. This is a difficult task without any datasheet.   Does somebody know the name of this component, is there a datasheet available somewhere?  Photo gallery of the display:          Product picture:
57484
What is this large metal bar inside my DMMs? One of them labeled it ST. They appear to be connected to the COM port or fuse. Is this just a big jumper for the 10 A ammeter?
53033
This may be a stupid question, but I have searched online for a little bit and can't seem to find my answer. I am working on a circuit board that uses buttons that i've never seen before. These buttons just have a metal lead around them and an LED in the middle (for lighting up the button I'd assume) but how does a button like this even work? I've attached some pictures to show you what i mean.    this is the back of the push buttons from the device
33221
If I want to disable beep sounds from stuff like bash, I add this line to "/etc/inputrc":  set bell-style none   Sadly, this doesn't work for some other events like GDM start-up and shut down. I thought that adding this line to "/etc/modprobe.d/blacklist.conf" would help:  blacklist pcspkr   That makes me wonder and doubt where the sound actually comes from.
81021
I have some experience with highfrequency circuit analysys. However I am a newbie in PCB design. I am analysing this circuit:  (starts on page 36) and regularly see things like "OMIT" for headerpins or components like resistors or so.  e.g.:   p41 (6/6): the boxheader(?) on the left. P40 (5/6): R48 on the dev board are two small surfaces with some soldering on it but no component apparently. I can hardly see myself (de)soldering resistors on my new dev board...   Why is this being mentionned? What do the people who made the PCB mean by this?  I mean if this part has to be omitted, why did they even place it on the PCB?  Thx
101865
What is the common English name for that "plastic part on the tip of a shoelace" which helps to easily insert the lace into the shoelace holes? (I'm not sure that's the correct name).  Edit: There are also metal parts of the kind.