I have a device (a 4.3inch Nextion touchscreen) that wants a big whack of current when it starts up (am told that this is typical of backlit tft displays). If it can't get the current it wants (almost 1A!) at startup time, it keeps trying to boot and failing and (they tell me) can eventually damage itself.
So, I'm trying to run it off a not-really-adequate BB power supply because I don't have a better 5v supply lying around. Sometimes (when already warm, as far as I can tell) it starts up OK and sometimes it doesn't, but I'm worried about the damage potential.
I live far, far from parts stores, which means a whole lot of delayed gratification and desperate improvisation. I do have more capable power supplies on order, but what with the holidays it may be weeks before they arrive, and it's frustrating not being able to run the device (safely).
So it occurred to me that I have a separate switch for the Nextion; I can power up the P/S first and then later turn on the screen. And I remember dimly that capacitors can store power and release it on demand. I already have an electrolytic cap across the 5v bus. If I had a big enough cap, and I turned on the p/s first and let the capacitor charge up, then turned on the display, would that take care of the initial demand?
What I don't understand, being not EE-savvy (though I'm learning a lot from tinkering with my Arduini) is the scale factor: how big a capacitor it would take to supply 1A at 5vdc for... I don't know, a few ms? Would this be a great big expensive thing with quarter-inch screw terminals, or could I get by with stuff from my parts box? My caps are rated in uF. Am I a couple of orders of magnitude away from the answer?
When I try to read online about capacitance and so on, I seem always to find texts so technical that I get lost right away The only wisdom I have managed to glean so far is that capacitors are "backwards" compared to resistors: when connected in parallel their capacitance is summed. So I was wondering if I could just stick several of my biggest electro caps (470uF) across the 5v and gnd bus