9 votes

Through holes vs pads for hand soldering

Soldering wires directly into holes in a PCB is not great- the solder wicks up stranded wire and creates a spot where the wire tends to bend and break off. For ease of re-soldering (assuming you don't ...
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8 votes

Through holes vs pads for hand soldering

Maximum customization: Readymade "DuPont" style wires with female connectors on the ends, that mate to male 0.1" headers soldered on your board. That's the mess on the left part of the ...
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  • 59.9k
6 votes

How common is it to receive PCBs with failed or weak vias?

I have seen it a couple times (many years ago with smaller Taiwan suppliers). Cracking around the part where the through-hole plating connects to the copper on the surface. I believe it's caused by ...
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5 votes

Through holes vs pads for hand soldering

In your case it might be useful to combine through-holes and pads: through-holes are much more durable but are nasty to (re)solder to because they have to be cleaned from remaining solder wires can ...
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  • 2,444
5 votes
Accepted

For a switching boost regulator, will putting the inductor on the bottom side of the PCB cause issues?

For switching regulators, loop area is usually the prime concern. Loops are not only in the XY plane, but are also in the Z axis as well. So, sometimes, you can get a smaller overall loop by placing ...
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  • 6,032
4 votes

PCB Ethernet instability - CM4 Breakout Board

Ethernet should be an isolated interface. Which means the PHY side signals and cable side signals should not be referenced with each other as they are isolated with the transformer. This isolation ...
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  • 89.7k
3 votes
Accepted

Do you understand this circuit?

Those two buttons on the left are intended to be read using an analog to digital converter. They don't provide a simple digital signal. There's probably a pull up resistor on another circuit board. ...
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  • 58.5k
3 votes

Does placing two optocoupler one below another in PCB design affect any signal?

Yes, you could do that. It would be better if they are directly on top of each other so there is no capacitive coupling through the PCB from input to output of the optos. I would also suggest looking ...
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3 votes

Is there another component on the pcb that will extend the leg of the component?

There isn't. You're either in jerry-rigging territory or making your own adapter PCB. In this particular case you could do that fairly easily since all you have to do drill holes and split the copper ...
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  • 47.2k
3 votes

What happens if input current of 2A is given to a L7805 rated of 1.5A?

The provided input does not matter. What matters is how much current the load consumes at 5V. The regulator can accept 12V input, and it can provide 5V at up to 1.5A. But it can't do all that ...
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  • 89.7k
2 votes
Accepted

How to import wiring csv into cad?

Ok, figured it out. import that csv into freeCad by running a script in the terminal which loads files: from FreeCAD import Base import Draft, Part file = open("good2dCoil.csv") wire = [] X=...
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2 votes

For a switching boost regulator, will putting the inductor on the bottom side of the PCB cause issues?

Glue is typically unnecessary if you keep the components on the bottom of the board small. The inductor will require extra steps (glue) to keep in on during reflow. Of course if you keep all the large/...
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2 votes
Accepted

Altium Single Layer Mode - Vias Color

This change was implemented in Altium Designer 21.9 and is called Accurate Layer Drawing. Accurate color usage in single-layer mode - switch to single-layer mode and the multi-layer objects are ...
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  • 27.6k
2 votes

What happens if input current of 2A is given to a L7805 rated of 1.5A?

Not knowing which brand or version of the 7805 you have, there's no way to know the specifics of how it will act. Many 7805 have internal current limiters. And thermal shutdown. One brand's datasheet ...
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  • 71k
1 vote

Is there another component on the pcb that will extend the leg of the component?

Options: Choose a part that fits, but delay production (that cap lead looks bigger than the hole !) drill hole (s), solder bottom side with resistor wire, add PU adhesive to base of cap, UV cure (...
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1 vote
Accepted

Altium Minimum Solder Mask Sliver error within thermal pad

Oh Altium my good friend. After an hour of looking at this I figured it out. The rule is checking the sliver as if the thermal pad wasn't there, and the vias were leaving a solder mask dam: The ...
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1 vote
Accepted

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

Schematic to work with an SD card

Card supply assumes that the SD card runs at a different voltage than your main host does. Power supply decoupling caps are just that, the typical caps needed for any power supply and ic. So yes, just ...
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  • 71k
1 vote

How to use MAX3232 RS232 to UART converter with ESP32

You have a problem with connecting the right capacitor polarity. Only C4 has the right polarity and you must reverse the others. A good thing to do is to check the voltage on pins 2 and 6 (V+ and V-) ...
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  • 2,577
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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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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  • 89.7k
1 vote

How design a PCB that hosts an SPDT relay

You'll need to look up two important concepts if you plan on using this to control line-powered equipment: clearance and creepage. Then, you'll need to determine how wide your traces need to be for ...
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  • 7,220
1 vote

How design a PCB that hosts an SPDT relay

Connecting it directly could damage the ESP32 and will not likely get the relay to operate reliably. ESP32 is 3.3V and the relay you show is 5V also. You can duplicate the circuitry on the module if ...
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1 vote

What happens if input current of 2A is given to a L7805 rated of 1.5A?

Regulating 12V to 5V with a linear regulator is a very inefficient method to do the job. With 7 volts dropped across the regulator more power goes into producing heat than actually is delivered to the ...
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1 vote

Via geometry parameters for controlled impedance in high frequency PCB

If you're working at 5 GHz with Rogers material, and return loss S11 is very important, then either do not change layers with an RF track or design the whole track layer change area as an RF ...
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  • 142k
1 vote

Designing A Circuit To Light An LED When Voltage Drops Below Threshold

Why are these two equations different? As far as I can tell the Sparkfun material is simply wrong. But it's hard to understand. For example, they say what will happen when \$V_{in}\$ is greater or ...
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  • 121k
1 vote

How to designate a specific portion of a design in altium

I'm using Altium 22.xx. To reset all designators on a sheet, I followed the above instruction of Tools -> Annotation -> Annotate Schematics -> Select desired sheet in lower left. But then in ...
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