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KiCad: Show keep-out/clearance around mounting hole

In KiCad version 6.x, you need to ensure that the Pad Clearance option is checked
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9 votes
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How is the CQFP64 package supposed to be soldered?

There's really not much documentation on the CQFP64. I found a document with all the dimensions of many CQFP variants, but I couldn't find anything about actually using them. I did find an example of ...
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5 votes

How is the CQFP64 package supposed to be soldered?

Can the golden frame and ceramic slab be removed before soldering, or should the pins be cut and bent onto the PCB? Normally no. Flip it over and it'll be ready to be surface-mounted (Atmel print ...
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Replacing a thermistor sensor with a common resistor to 'trick' it

We are now switching to a more powerful cooling method and wants this threshold gone. If you cool it better, then it will not reach the temperature threshold, right? So what exactly is the problem? ...
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1 vote

How can I repair peeled through-hole solder pads and trace?

Normally you'd scratch off some of the solder mask from the trace that's still intact with a scalpel or similar, then solder onto the exposed copper. In this specific case you can probably just glue ...
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1 vote

Replacing a thermistor sensor with a common resistor to 'trick' it

Yes, can be done easily: Check the thermistor (typically possible through datasheets or a visual inspection). Look up the resistance table for that thermistor (easily found on Google or similar). You'...
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3 votes
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What is the name of this electrical component symbol?

That symbol is called an "outline",in this case it approximates the D shaped cross-section shape of a TO-92 package. image credit RS-online The writing ...
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1 vote

What is the name of this electrical component symbol?

If the SPK CH1 header or wires were included the the BJT would have likely been included. Since you did not mention any problems this omission was intentional for some other purpose. (Option) The EBC ...
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1 vote

Problem with LED lamp PCB

Sometimes we don't have enough information to solve your problem. The next best thing, then, would be how to get more information. So, my thoughts, in order, are... Find a way to stop destroying the ...
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2 votes

Controlling ADC (on/off) with microcontroller

Sounds like a generally bad ideas; don't switch the power to something that you can even simpler put into a power-down mode. In power down, your adc uses 400nA typically; the whole support logic you'...
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1 vote

How can I repair peeled through-hole solder pads and trace?

One way is to use a fiberglass brush pen (also called a burnishing pen) and scrape away the solder mask on the trace and solder a wire from the pin to that. Sandpaper or a knife works too but you have ...
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1 vote
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How to connect 2 (and more) PCBs together to make them semi-modular?

The solid state lighting (LED) industry developed a series of connectors specifically for your application. For example from Digikey. https://www.digikey.com/en/articles/connectors-for-solid-state-...
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1 vote
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How to measure the power of two small solar panels independently and combine the power?

This is a very simple and cheap first approach simulate this circuit – Schematic created using CircuitLab It is much easier to measure the individual current of the panels than the voltage. ...
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0 votes

Beginner Question - Solder won't stick to a certain wire

Use flux and use the right flux. If you are using lead free solder use flux that is also more compatible with lead free solder. The best one I've found (so far) is chipquick SMD291. I've had no ...
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0 votes

Beginner Question - Solder won't stick to a certain wire

A tin plated copper wire is very easy to solder. But for a lead free solder with some copper in it you need a soldering iron with higher temperature. The isolation of a wire wrapping wire should be ...
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2 votes

Short circuit broke a P-channel MOSFET

If you place a 10mF cap (the one in the upper right corner) on the p-mos drain, I would imagine that the inrush current while the cap is charging is what broke the MOSFET. That is, the cap is now ...
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0 votes

How should I use this voltage regulator for best efficiency?

If you don't need an exact regulated supply, you can put a schottky diode between battery and the common board supply. If the MCU is aware of the battery voltage, it can bypass the diode with a P ...
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0 votes

Altium designer transfer to pcb issue

you can select the components from schematic and can go to (part action -> update selected from libraries) then select the footprint manually, this problem occurred to my fiducials which was not ...
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1 vote

How should I use this voltage regulator for best efficiency?

Assuming linear regulator. What features of the voltage regulator should I pay attention to for lower power consumption? Quiescent current, obviously, including feedback resistors. That pretty much ...
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2 votes
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How to infer resistor size from the manual of this microcontroller board?

The CAD files that @TimWescott referenced contain the PCB layout (in the schematic zip, not necessarily where you would expect it). As typical for ST, they are in Altium. The footprints look like this:...
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2 votes

How to infer resistor size from the manual of this microcontroller board?

A solder bridge is either a blob of solder across two specially shaped pads, or a 0-ohm resistor, also called a jumper. That's it! The name of the thing itself tells you what to use to short it: ...
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2 votes

Fiducials on PCBs

Fiducials are an aid to align the pick & place machine coordinates to the physical PCB (x-y & angular offsets, and scaling). The fiducial location is located by optical means. That means the ...
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0 votes
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Voltage divider on PCB gives inaccurate output

Thanks all for your answers and comments. It was indeed what @Spehro Pefhany posted in their comment. Vs is connected to an analog MUX (I had missed this somehow) and I had not applied power to that. ...
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3 votes
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PCB connector 0.05" pitch

That is a parallel-mate, wire-to-board connector. 1.27 mm is not a standard pitch. It's either 1.2 or 1.3 mm. I used my connector identification utility to identify it as possibly one of these: MANUF....
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2 votes

Voltage divider on PCB gives inaccurate output

You said that you disconnected the zener and capacitors, but you did not say whether or not Vs is still feeding some other part of the circuit. See if there is something else connected there. If that ...
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1 vote

Voltage divider on PCB gives inaccurate output

Since all other components have been removed besides the two stacked resistors (68K and 33K), the lower than expected Vs voltage must be influenced by the voltmeter's internal resistance. Solving for ...
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0 votes

Altium trace symmetry

I normally just fiddle with them until it looks right, but then, I'm like that... Some things that can help: Get in the habit of changing origins and grids. This can be done with E, O, S and G, G. (...
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1 vote

Routing USB signal on RP2040

For USB FS stubs of an inch length – what you seem to be showing – it doesn’t matter much what you do in terms of impedance. Just route the traces close together over a ground plane and all is good.
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0 votes

Altium trace symmetry

The traces should be straight lines between each pair of pads. You’ll have a nice looking fan without having to align anything. There’s no point to this 90-45 layout when doing such pitch-adapting ...
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1 vote

Routing USB signal on RP2040

USB connectors are compatible. If you use USB 3.0 but use only USB 2.0 pins, it is equivalent to plugging a USB 3 device to USB 2 socket, or plugging USB 2 device to USB 3 socket. "Best" ...
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1 vote

Flush Mounted Threaded Through Hole on PCB

Looks like M2.5 "Zero" Height SMT Threaded Insert P/N 24929 by Keystone https://www.mouser.co.il/ProductDetail/Keystone-Electronics/24929?qs=Znm5pLBrcAJPd1Bwfdw1vA%3D%3D
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2 votes

Drying populated PCB with compressed air

There is no proper psi and distance because these two values are not even remotely close to determining the mechanical loads imposed on the parts. And the parts’ sensitivity to mechanical loads varies ...
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1 vote

Transmitting an RS232 Signal over Wireless/RF. Can this be achieved?

In a production environment, you can't afford stuff that doesn't work. If both ends of the wireless transmission are 20m apart, then the user on one end won't be able to see the screen of the computer ...
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1 vote

Transmitting an RS232 Signal over Wireless/RF. Can this be achieved?

A device that does this is called a Radio Modem. They work like a phone modem, but using RF instead of audio. You basically connect your RS-232 devices to them, and set up the communication protocol. ...
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1 vote

What are the markings on this PCB?

The markings are not very relevant. This is a 4-layer board and you'll have to reverse-engineer it, i.e. figure out the connections, and re-draw it using KiCad (realistically). The board looks to be ...
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2 votes
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What are the markings on this PCB?

It appears to be an industrial control board made by Siemens, which may include a Modbus interface. You'd have to ask Siemens what the markings mean, or find a circuit diagram or device guide that ...
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0 votes
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Differential Microstrip Impedance Calculators Giving Conflicting Answers

JLCPCB and EverythingRF use the same formula which only applies to circumstances where the trace-width-to-dielectric-thickness ratio is less than 1 (W/H < 1). (EEWeb has a good explanation on their ...
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0 votes

Do I need a GPS simulator to design a device that contains a GPS receiver and a pre-designed antenna?

There are plenty of traps in designing RF circuitry, and (in the case of GPS) it is quite easy to end up with something that doesn't work at all, and (in the case of GSM) doesn't conform to the ...
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2 votes
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Do I need a GPS simulator to design a device that contains a GPS receiver and a pre-designed antenna?

RF design is not trivial. "It looks exactly the same" doesn't mean it will work exactly the same. The very material of the PCB makes a difference to how the signals behave at the ...
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2 votes

Two separate PCBs and common ground for UART communication

A direct connection between two GNDs with jumper leads is enough.
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3 votes

Two separate PCBs and common ground for UART communication

If that is using standard UARTs, you absolutely need the ground as reference for the Tx and RX. Where you see on two connections, then the two ends must have a common ground that is not shown there. ...
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0 votes
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Using a 5V voltage regulator with a 5V input

the professor stated that, even if the input will be the same as the output, one should normally use a voltage regulator regardless. Nope. A linear voltage regulator can't produce an output voltage ...
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0 votes

Using a 5V voltage regulator with a 5V input

You can't get 5V outof a linear regulator supplied with 5V. There is always a voltage difference between input and output for a linear regulator. The AMS1117 you specify in your schematic requires a ...
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0 votes

Which resistor/solution should I use?

I would remove the 3 other resistors and place a large SMD2512 4 Mohm resistor with HV capability vertically between the pads of R28 and R84. A flexible wire from the R84 pads to the left side across ...
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0 votes
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Connecting 2 layer PCB coils together

The voltage polarity of adjacent coils will be opposite because the polarity of the magnets is as well. If you ignore this, every two coil voltages will sum up to zero. Consider a ferrite plane like ...
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  • 1,924
2 votes

What does this symbol on PCB mean?

I don't know what it's doing on a circuit board, but I've see that symbol on lamps. It means "if you break the glass window, replace it with a new one." I've generally seen it on 230VAC, 500 ...
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0 votes
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Which resistor/solution should I use?

The circuit board has been fractured, probably due to something heavy soldered into it or some pressure or impact from outside if shipped without housing. You should fix that with some epoxy-glass ...
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0 votes

Which resistor/solution should I use?

It looks like those are four 100*10^4 = 1 MΩ resistors in series (that's what the '1004' means). It is probably for measuring a high voltage. You can use a standard 1 MΩ like this: which might be ...
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4 votes

Estimating PCB Trace Delays

Well, this dives into the topic of high-speed board design, and that's fine. (going a bit more basic, also for future readers) Basically, when we're talking about rapidly changing currents coming out ...
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