You can calculate a materials resistance using its resistivity and dimensions. For a simple wire, the formula is R = p*l/A, where p is resistivity, l is length, and A is area (cross sectional. Imagine cutting the wire, you'd see a circular cross section).
Some materials like copper have very low resistance.
Some materials like oil have a very high resistance.
Some materials like carbon have a resistance somewhere in between, but generally fairly high.
Resistors use a strip of carbon to make a high resistance path.
Resistance in a switch is typically minimized by design, so introducing a switch or button should not introduce a lot of resistance. It is tyically better not to use switches of this type in signal critical or high power applications (e.g. sound or battery charging), but charging up a small capacitor or powering a small dc circuit should be fine
To measure resistance, one can use a multimeter. This makes use of Ohm's law. Ohms law shows that
V=I*R
Where V is voltage, R is resistance, and I is current. When a small voltage is applied across your component, the current is measured. Then using the current and voltage, it can figure out what the resistance is. It shows it to you on a display so all you have to do is touch the probe tips to the two legs of the switch.
For a switch this will typically be less than 1 ohm. If you buy from a reputable distributor (e.g. digikey, mouser, arrow, farnell, even LCSC) you can get the "datasheet" and look for the constact resistance. This might be a bit harder with ebay/amazon/aliexpress parts, so just stick with a multimeter.
A cheap handheld one is fine, but I'd say prob look for an EEVBlog or other video looking at good cheap meters; you can get pretty good stuff without breaking the bank. Don't stress over it though; any multimeter is better than no multimeter
A 12 volt battery w/ a pot and a few other components. The plan is it wont be running more than 5 milliamps through it. I ended up getting this so not exactly a conventional momentary switch.
That is pretty much exactly a conventional momentary switch. It just happens to be packaged for use controlling something a little different.
It should be fine for your application.
One thing to note - the contacts will probably "bounce" as the switch is closed. Produce a string of momentary connections and disconnections for, oh, say the first few thousandths of a second. That's perfectly normal for a mechanical switch.
That won't matter in its intended application. But if you are using it with electronics, say counting the number of times the switch is operated - the results can be unexpected.
You can look up "debounce" to see how this can be worked-around.
Thanks, I appreciate the clarification on the switch just having a different housing. I'll have to do some further research on "bouncing", interesting stuff.
Faster or more charging requires more power and therefore more heat is produced. If your phone is at 20% and you charge it, it will be charged at a higher rate than if you were charging it at 90%.
If you have an inductive charger, a wireless charger, those heat up due to the nature of their design when in use.
Edit: Don’t rule out malfunction as the cause. The charger, cable, or phone could be creating an unsafe operating state.
For something that’s not switching at a high frequency, slow rise and fall times are fine as long as you are staying within the safe operating area of your MOSFET. A 10K gate resistor could certainly work, but it will depend on your MOSFET and load.
That’s good. My switching frequency is a few times per hour.
I am a little bit concerned that the slow rise/fall time make the MOSFET go outside its operating parameters for a fraction of a second. The resistance gradually changes meaning the mosfet will dissipate more power but also less current will flow.
So if you switch many times per second the gate capacitance with the resistor acts as a low pass filter reducing the gate voltage.
Your 2nd best bet would be to get the pin spacing, and filter your search using that.
Your first best bet would be to just replace both ends.
I settled on a ‘standard’ and just bought a massive kit of each of those connector types- wire-wire, wire-board, wire-panel in M and F, in various pole counts. Buy once, cry once.
Well, feeding voltage in that range to 24V fans would be fine, but “19 to 24V” makes it sound like a USB type-C charger or something which communicates with the device to set its output voltage. A power supply should have a single voltage.
Unless it’s one of those generic power supplies with a switch to set the voltage?
Copper or silver-based should be lower resistance. These conductive paints tend not to be very conductive, the carbon stuff is essentially making a thin-film carbon composition resistor. Good for repairing rear window defroster heating elements, not so great as a 0-ohm trace in a keyboard. For short (<1cm) wires it’s usually not too bad, but with the amount of damage I’m not sure you’ll be able to repair the thing.
It looks like it might be from a Model M-style keyboard. Unicomp sells those.
Unfortunately the shipping fees would kill me since I’m in Europe, I really wish I could buy a new membrane but it seems like I need to do the repair myself.
Would copper tape suffice as a low resistance trace?
Worth trying. It’s already broken, you can’t really make it much worse. It’d probably work, and worst case you’re back where you started & paying for expensive shipping.
-i live in the country, power outages happen, I cannot reliably prevent things from turning on all at once.
-my other mixers make noise when turned on, but they are not loud enough to kill speakers; even so I do try to turn things on in the proper order. This one is dangerously exceptional and won’t be used if this can’t be fixed.
There are timing relays for under $50 that can delay the power to the amps for a few seconds. You just need to buy a 230V model (for input and switch) that has the current capacity for your sound system.
Very weird looking tearing, but if you are playing 24, 25, or 50 FPS content on a TV or monitor that is locked to 60HZ it is going to tear, some handle it better than others.
I suspect your output is set to 60hz or something and you are watching content that isn’t at either 30 or 60 and your playback software isnt doing autoswitching (kodi, plex etc do this, but not web browsers or apps like netflix)
So it’s not a hardware fault, its just the reality of watching media on a computer with an external display, so it’s a software configuration problem.
Also, considering the severity of it, are your video drivers up to date? that amount of tearing is close to what you’d see when running standard vesa drivers like when you have no video driver installed at all.
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