I’m looking to fix a problem with back emf in a motor circuit where I have recently lost a few boards. I am adding better fly back diodes (better than the MOSFET body diodes) and another source I see recommends a 100uF cap between Vmotor and GND. To me this seems counterintuitive because, if I understand back emf well, for a brief period of time the voltage supply become inverses and the GND is at a higher potential than the supply due to the inductor. So why use an electrolytic capacitor if it cannot withstand reverse voltages very well?
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https://i.imgur.com/mDzffyz.jpg
This is the power supply board. It's the large capacitor in the bottom middle (C 911).
In the service manual the description is:
C 911 | CP185P040A10 | C-ELE | 450V 220M LI B45
and it is described to be 'the block capacitor'
For comparison to how this manual describes the average electrolytic capacitor, here's how it described the large capacitor to its left (C 951):
C 951 | CP182P114A40 | C-ELECTROLYTIC | 250V 100M-M 16X31.5
I know the __V is volts, the __M is uF (not sure what M-M changes), the __X__ is the dimensions, but for C 911 I can't figure out what LI and B45 mean, or why the name is different. I dont think its bipolar because the manual already has a name for bipolar electrolytic caps.
Thanks!
What size resistor should I use to safely discharge a 50v 4400uf electrolytic capacitor?
any electrolytic capacitor engineers here?
i have electronic devices that use electrolytic capacitors (Snes, PS2 Slim consoles, CRT TV) some of these devices and electrolytic capacitors were manufactured in the early 90’s but I don’t know the brands of these capacitors
my doubt is about long-term storage of these electronic devices will cause failures and problems in these electrolytic capacitors?
#Solved! Check my edit below!
I just assembled and tested my ordered PCBs that use an atmega328p and a pair of 595 shift registers and transistors to drive a 5 character 7 segment display. Upon plugging it in to USB with the atmega out of the socket all is well and nothing happens, but after putting the atmega in its place my computer's USB crashes and the atmega as well as the shift registers both start heating up. Everything appears to be wired the same as on my test breadboard, EXCEPT for "smoothing" capacitors that I added to the PCB design without doing diligent research. I have a 10uf electrolytic capacitor directly between the 5v+ and GND at the USB connector, as well as another one between 5v+ and GND close to the atmega itself. Could that be what's causing my heating and shorting issue?
Sorry I don't have a picture yet I need to o clean up the kicad diagram to make it even worth trying to read.
EDIT: Turns out the USB mini connector in my Kicad schematic was somehow reversed! I have never worked with USB mini connectors before so I was just going off the pin wiring in Kicad and wasn't showing experienced enough to spot the mistake. I was powering the entire circuit backwards! It was an easy fix, I just desoldered the USB mini socket and installed a new one in the same holes but on the backside of the board instead, effectively flipping the pins around. Everything works great now and thankfully nothing got damaged! Thank you all very much for your help and guidance!
cant wait rather
Is it normal for 100v rated 105c electrolytic to let out a magic smoke when operated with SMPS at 94.5v ? Faulty cap or something else, i cant check the DC waveform to see if theres a voltage spike or something since i dont have an oscilloscope, but the DC rail measures at 94.5VDC, brand new 100v 4700uf nippon chemi-con capacitor
So.. I need to recap a old "plague" era motherboard (2005)
It's essentially ewaste im trying to save from the landfill and use in a project.
I don't want to spend 10 dollars on something good like panasonic caps.
so I did the sin and bought some "low esr" caps from a supposedly good Ali Express seller.
Anyway the caps are mostly coming in "okay" (not great but within reason) ESR wise.. but im seeing Vloss around 2-4% on some of them with my cheaply component tester.
Thing is.. im not all that familiar with Vloss and how to interpret it..
I think this is referring to voltage leak.. but again not real sure how big a deal this is.. I've seen high%'s on bad caps but on good caps.. what's acceptable? when to worry?
thoughts?
Hello. Gradually I've been getting more and more unwanted noise in my signal chain and have narrowed it down to this unit. It's an an M-Audio MobilePre USB Preamp from 2002. Do you guys have any recommendations on how to go about choosing suitable replacement caps, especially with regard to the smaller, nearly identical ones?
https://i.imgur.com/QsU1IEM.jpg (unit internal PCB)
https://i.imgur.com/v8bJxwP.jpg (unit external layout)
The values for the caps are as follows, all are branded as G-LUXON..
4x (green) - 47uF @ 63v [RN 85c 411A (M)] {bi-polar}
15x (yellow) - 47uF @ 63v [SM 105c 410C (M)] {polar}
27x (red) - 10uF @ 16v [SX 105c 411D (M)] {polar}
3x (blue) - 10uF @ 16v [SX 105c 410C (M)] {polar} <------???
Thanks!
Okay, this feels like something that should go in r/shittyspacexideas. But maybe it works?
What if I connect an electrolytic capacitor in reverse and run a current through it? Will it blowing up create a good enough spark to light an APCP rocket motor?
Better yet, can I use it as a pyrotechnic ignition sequence for a small charge to deploy parachutes.
This sounds like a really stupid idea, but I'm not sure why.
Will this work? Having trouble finding a specific electrolytic capacitor. Or is it a generally good idea to install what the design calls for?
It’s for the 1776 multiplex delay
