hardware26

@hardware26@discuss.tchncs.de

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hardware26,

As you said before power on capacitor is discharged. Right after power on capacitor is still discharged, so voltage on capacitor is zero, so reset pin has Vcc. With time capacitor gets charges and voltage across capacitor increases and reset voltage becomes closer and closer to ground, until it is ground. But it is important to consider what happens at power down too. At power down capacitor is charged. If power source becomes high impedance at power down, then reset pin will probably go down to zero in time but may take a bit time depending on what source exactly does. But if power source is connected to zero at power down reset pin will observe minus vcc and slowly go up to 0. If reset pin is sensitive it may be a good idea to protect it with a diode.

[PCB Review Request] ESP32 small usb board (postimg.cc)

The purpose of this PCB is to be small, have ok RF performance, and use USB as main power-source and interface. (Off course it has UART if USB is not available) this is just a somewhat challenge I set myself to design a esp32 PCB with the IC without a already made module....

hardware26,

Depending on the power consumption, you may consider not using thermal relief while connecting thermal vias for the chip (component 57) to ground layers. But this may make soldering harder so do it only if needed. Thermal vias are so close that they form 3 long dents in 3v3 plane. It is good practice to put vias a little far apart so that planes can go through between vias. This can be important since sometimes lowest impedance can be obtained when current is flowing between those vias. If you don’t need to fit 15 vias there, you may consider reducing the number and separating them a bit. You can also check the design rules for minimum copper width and minimum via clearance for your manufacturer and enter them in your CAD tool.

hardware26,

Third siblings who were born right after cameras got affordable have the most pictures.

hardware26,

Is this an AOE2 reference or is it historically correct? I knew I should not have learnt history from games.

hardware26,

I was way off:)

hardware26,

It was, thanks

Advancing Cu-Cu Hybrid Bonding: Overcoming Challenges for the Future of Semiconductor Packaging | Microwave Journal (www.microwavejournal.com)

As solder bump pitches shrink, several issues arise. Reduced bump height and surface area for bonding make it increasingly difficult to establish reliable electrical connections, necessitating precise manufacturing processes to avoid errors. Critical co-planarity and surface roughness become paramount, as even minor...

Jumping Over Thermal Cycles Accelerates Thermomechanical Fatigue Simulations (semiengineering.com)

Although you are probably not aware of them, dozens of electronic control units (ECUs) — printed circuit boards (PCBs) in metal or plastic housings — exist in your car to control and monitor the operation and safety of your vehicle’s many control systems. These units must work for the lifetime of your car, during which...

hardware26,

2

hardware26,

Sponge may be burning as well. Do you keep the sponge moist?

hardware26,

You can try checking whether the 54v supply has any voltage spikes if you haven’t already. 60-to-5 converter is most likely a switching converter and they draw high current instantaneously and can cause spikes if not filtered properly which may affect the functionality. This may not show up in DC voltage measurement, and daisy chained boards may still function if they are filtered well. One of the daisy-chained boards may be causing the disturbance too, and maybe top board is filtered well but bottom isn’t for some reason, maybe a soldering error(e.g. filter capscitor ground connection, poor soldering may be conductive but with high inductance, hindering filter functionality). So it is good to check supply quality. Also what do you mean by not powering up? Is 3.3v not working? What about 5v?

hardware26,

Lifelong mental trauma as legacy

Help Bypassing Timer on LED Lights

Hi all! I recently purchased some push-lights for my kitchen from my hardware store, and I stupidly didn’t read the package that said that they shut off after 30 mins. This is super inconvenient in my dark kitchen, and I can’t return them. I figured I might as well tinker with them, and any help would be greatly appreciated....

hardware26,

Can you read what u1 and q1 are in the first image? Q1 looks like a transistor switch and u1 might be a counter. It may be counting a clock or it might be a comparator checking whether a capacitor is charged or discharged to check time. Is there any components on the other side of the board? I would expect a capacitor or oscillator at least for timing.

hardware26,

If you are completely new I suggest watching a tutorial. Otherwise some basic tips could be

  1. if oscilloscope has multiple channels, make sure the channel you connected is the channel nel you see on the screen
  2. make sure you did the ground connection. You need to connect both signal and ground tips if the probe
  3. make sure voltage range is fine. If you use a large range in the screen, little amplitude you got may seem like a flat line.
  4. calibrate your probe, if oscilloscope has that option. But an uncalibrated probe doesn’t explain flat line, it would explain distorted square wave, for example.
  5. Use another probe. They can get broken. If it is broken all you will see will be the noise the cable pics up like an antenna.
  6. separate the issue. Connect probe ends to a battery with k own voltage and see what you receive. If it doesn’t work, you know either probe or oscilloscope is wrong.

List can get longer really, but I think a tutorial and these can go a long way for the beginning.

hardware26,

It should do the trick I think. If you are working on electronics a lot, you may consider buying a breadboard and variety of resistors, capacitors and nmos, pros, bjt transistors in bulk for quick fixes instead of waiting for orders to proceed. Have fun

hardware26,

Well done, good to hear

hardware26,

Problem you are having could be

  1. output impedance of the signal generator you use to generate the square wave. When you set it to low, output impedance of the signal generator builds a voltage divider together with the internal pull up, and the device ends up sensing a higher voltage than "low". This is something you can see if you have an oscilloscope, try to hook up a probe to the input and ensure whether you get what you set in the signal generator.
  2. some signal sources have no or limited capacity to drain current. And when you set it to low, this is exactly what it us supposed to do, drain current from the internal pullup.

As you mentioned in another comment, solution is a simple buffer. This could be an opamp, but even a simple nmos transistor should suffice (open drain as you said). But you need yo be careful with current ratings of the transistor, which you can easily calculate by dividing 5V by the pull up resistor. Send a message if you need help.

Before these, I suggest you yo use an oscilloscope or multimeter to measure the voltage when it is supposed to be low, and see that in fact the problem is that voltage at the input doesn't go "low".

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