I don’t want this too be too late so just gonna throw this up rn and edit it later with my notes later so look forward to learning about capacitors :)
Fuck it we ball, capacitors what I know of them is they help motors start. In HVAC we got two of them run capacitor a and start capacitors. Motors that are aren’t 3 phase need a phase shift to get them going. Thing is motors need power coming in to be just right if a start capacitor is left running it will draw locked motor amperage and shut it all down so it’s put in series with a PTC relay (once this gets too hot it opens and shuts off power to the start capacitor) letting just the run to do it’s thing.
Capacitors need to be tested by isolating and discarding them and checking for capacitance in microfarads. The rating is usually on the capacitor and needs to be within ±10%. On the capacitor the voltage is supplied too with 2 different values. The higher value is the real one so this means you can use it on a size lower if you want. I’ve heard of testing them under load to fully get how they work,you take amperage on the start winding then multiply by 2652 then divide voltage across the capacitor to check if it’s good.
Anyway capacitors got oil in them to dissipate heat, thin plates of metal and plastic between them to insulate. These are used to store power, try not to fuck with them even unplugged they can still hurt you. The oil can also be an issue obvs. Anyway they store and discharge voltage they don’t boost it, at least in ac systems. If you read a higher voltage it’s most likely back EMF generated from the motor as it runs. Anyway you gotta take this into account when sizing relays.
One more thing capacitors when wired in series will have reduced capacitinace, 1/C +1/C but wired in parallel you just add them C+C. Probably doesn’t mean much to people but for electricians it’s useful if you don’t have the right size. Only connecting them in parallel is probably the only reason to do it practically.
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i am familiar with the objects known as capacitors although only in the context of electric guitar / basses where they are used to filter the output and create “tone” we call it 1950s tech although im seeing they are apparently much older than that.
also my dream self told me to cut my hair short and bleach it 🤔
Pretty dope I mostly knew them from first in cameras for the flash and then HVAC for motors. My dream selves tell me stuff too but never about my hair
I saw a guy turn a square wave into a sawtooth wave just by adding a cap to the output line yesterday in a video. it made sense in retrospect but I just never thought about it (and yes it also coloured the sound a lot which was also surprising. do caps have frequency responses??)
They do! The frequency response of an ideal cap like @sodium_nitride@hexbear.net and @GiorgioBoymoder@hexbear.net describe is quite simple: infinite impedance at DC, dropping to low impedance at high frequencies. Specifically the formula is |Z| = 1/(2*pi*f*C) where |Z| is the magnitude of the impedance in ohms, f is the frequency in hertz, and C is capacitance in Farads.
But real world caps have much more interesting frequency responses! A real non-ideal cap has both inductance and resistance as well. In general, capacitors will have a resonant frequency where their impedance is at a minimum, and above that frequency they behave like an inductor while below they behave like a capacitor:
Depending on the type of capacitor, they they can also introduce significant levels of distortion to the signal since some behave non-linearly: their capacitance changes with the voltage of the signal. I think multi layer ceramic caps are notorious for this and are usually very undesirable to have in signal paths. And I think tantalum caps exhibit this as well, though less severely. Here is an example curve:
it’s shocking to me how much simpler analog audio processing really is than DSP, I’m sure if you’re wanting a good sound there’s still a lot of math in analog but “just throw a cap in there and see how it sounds” is fascinating to me for silly little projects I want to do
Tbf it’s going to introduce distortion even if its linear, since for perfect signal transmission, you want a rectangular frequency response (the allowed frequencies are unchanged while unallowed frequencies are zeroed). Capacitors and any real system will have slopes and ripples.
This is true, I should’ve specified nonlinear distortion. Specifically harmonic distortion, and maybe intermodulation distortion?
Caps, inductors (or chokes/coils) and resistors are the 3 basic linear electrical components. Capacitors are the exact opposite of coils, electrically speaking.
Caps short out AC (but block DC) signals, while coils short DC signals and block AC.
Mathematically speaking, capacitors represent integration (they integrate current, aka store it up), while inductors represent differentiation (their voltage depends on how quickly the current is changing).
Both integration and differentiation show up as frequency responses, but flipped.
By combining them with resistors (which just multiply current to produce voltage), you can create any kind of linear differential equation/system.
yes they do. In an extrememely basic sense, capacitors block low frequencies but pass high frequencies. for example with a DC voltage the capactitor “fills up” with the constant flow of electrons and that built up charge repels further flow. in contrast the electrons in a circuit with quickly oscillating voltage will change direction before the capacitor has time to fill up and slow the current.
capacitors are chiefly categorized by their capacitance (unit name farads) which is essentially the amount of charge they can store. this means that, basically, the higher the capacitance the lower the frequency it will let pass. see also, “high pass filters”
sick I’ve been meaning to learn about how analog filters are built as I figured it would be a pretty simple circuit. I’m gonna have to breadboard about this