Questions tagged [electrolytic-capacitor]
An energy-dense polarized capacitor type, used in low-frequency filtering applications.
31
questions with no upvoted or accepted answers
2
votes
0
answers
123
views
What would be the cause of measuring AC voltage across a LM7805?
This is my first time here so I apologize if I don't provide enough information. I am trying to repair a centrifuge that is giving an error on its LCD display. Though the service manual doesn't say ...
- 21
2
votes
0
answers
55
views
Question about series-connected (pseudo-nonpolar) electrolytics
Another Q&A on this site ("Ceramic caps vs electrolytic. What are the tangible differences in use?") contains good information on capacitors in general, including parameters I wasn't ...
- 31
2
votes
0
answers
88
views
Aluminum Electrolytic Capacitor submersed in synthetic (PAO) oil
We are testing solar water pumps which have the 3phase inverter for the BLDC in the down hole pump. The boards (one power board, one controller board) are submersed in the lubricant oil that is used ...
- 21
2
votes
0
answers
353
views
Replace filtering(?) capacitor on CRT deflection Board
I am doing partial recap on CRT monitor Sony PVM 20m2e. (monitor was working, but RGB lines at the top of screen which should be hidden were visible and geometry is not top notch)
I desoldered C584 ...
- 131
2
votes
1
answer
131
views
Where to place a cooling fan supply capacitor
I want to run a ~2W, 12 VDC fan in an EMI-sensitive environment.
The schematic is shown below. Due to the spiky current draw, I intend to place C1 and C2 right by the fan connector, so high frequency ...
- 22.5k
1
vote
0
answers
98
views
How can I measure the voltage of a capacitor using multimeter?
I'm new to electronic and trying to measure a capacitor (Aluminum Electrolytic one) using a multimeter. The cap is already charged. What I did is to touch the positive leg of the cap with the red ...
- 111
1
vote
1
answer
108
views
How to visually distinguish metal film and ceramic capacitors (leaded)?
This question only involves the leaded components.
Electrolytic capacitors are each to recognize since they are usually in cylindrical cans. However, I am not sure about distinguishing the other two ...
- 749
1
vote
0
answers
133
views
Tantalum capacitor at low temperatures
What could happen to a solid tantalum capacitor that operates below the lower temperature range defined by the manufacturer (-55°C)?
From my understanding, there would be a performance issue with ...
- 11
1
vote
0
answers
197
views
Discolored negative lead on electrolytic capacitors
Would the discoloration around the negative lead of these capacitors be a sign of failure? If so, why would the negative lead darken instead of the positive - or both leads.
They are Maron EFM 35 ...
- 71
1
vote
0
answers
502
views
How to Determine Input Capacitor Value for Peak Power Requirement
For flyback SMPS, how do we know that our input capacitor value is sufficient for some peak power requirement?
I understand that bigger input capacitor will have more advantage on this peak power. ...
- 377
1
vote
0
answers
164
views
1V Overshoot and Undershoot on Power Rails of LTE Module
I have designed a PCB (four layer) having SIM7600I LTE Module. The Stackup is:
Signal & Component Layer with Ground Pour
Internal Ground Power Plane
Internal ...
- 962
1
vote
0
answers
830
views
Decipher Surface Mount Aluminum Electrolytic Capacitor Markings
I am repairing a Definitive Technology BP-7004 Super Tower's power supply / amplifier that makes a buzzing noise when it is cold. After it warms up, the buzzing slowly fades away. I've attached an ...
- 11
1
vote
0
answers
128
views
How can I improve conducted emission caused by a bad primary electrolytic capacitor?
I recently got the job to find out how to pass conducted EMI tests with a bad electrolytic capacitor after the rectifier in a power supply. The background is of course, that the new type is cheaper ...
- 720
0
votes
1
answer
31
views
Multiple smaller capacitors on power rail for NeoPixel / WS2812B strip
I read in the AdaFruit guide that a 500-1000uF capacitor is recommended on the power rail.
However, electrolytic capacitors in this capacitance are quite large. Depending on the length of the strip, ...
- 101
0
votes
1
answer
68
views
Cyclic Voltammetry for a Capacitor - Positive Current, Potential is decreasing?
In the boxed red region, why is the potential decreasing when the current is still positive? To my understanding, when the current is still positive (i.e. not changing direction), the capacitor will ...
- 1
0
votes
0
answers
22
views
Lithium Ion Battery : Electrolytic Capacitor At Buck Converter Output
It is recommended not to parallel electrolytic capacitors with a battery due to the leakage current of the electrolytic capacitor (which is small but worthy of consideration over large time periods) ...
- 437
0
votes
1
answer
57
views
Power schematic questions
I received a guitar pedal in poor condition and looking to repair. Checking through the schematic, it appeared the electrolytic caps were installed backwards. All other picture I could find online ...
- 1
0
votes
1
answer
87
views
Calculate capacitor charging constant time connected to battery and boost converter
I know the formula to calculate the constant time for capacitor is t=RC and for full charge t=5RC.
In the following example there is not resistor in the circuit but of course we are not in the ideal ...
0
votes
0
answers
172
views
Powering RTC DS3231 through BAT pin while keeping the coin cell battery in place
I'm working on a battery-powered DSLR camera controller with a MCU (ATMEGA328P) that spends most of the time in deep sleep and a RTC (DS3231) that wakes up the MCU a few times a day to take a picture. ...
- 183
0
votes
0
answers
76
views
Is a choke required on power supply input, 50 Hz single-phase 230 VAC
I have a 2 kW 20 kHz ultrasonic power supply which trips input power when I turn it on.
I disconnected the choke between the diode bridge + and capacitor +, and connected from the bridge to the ...
- 1
0
votes
0
answers
60
views
What could be the cause of a limit in the voltage supplied to a capacitor?
Recently I built a very basic 2-stage coil gun for a school project. Each coil was powered by an electrolytic capacitor. In order to charge the capacitor, the coil connected to an IGBT (insulated-gate ...
0
votes
1
answer
25
views
Proper material for testing capacitor at 105°C
I've built a circuit to estimate capacitors life. I need to test it at 105°C. I have no idea which material to use for the chamber that I want to put my capacitor in and control the temperature.
0
votes
0
answers
127
views
Capacitor Lifetime
Can anyone some sample calculation on how to calculate the lifetime on an Aluminum Electrolytic capacitor who's Endurance value (Assumed as Lifetime value is 2000 hours at 105degC).
The manufacturer ...
user220456
0
votes
1
answer
68
views
Decoupling capacitors - placement close to DC output
I have a general question regarding the placing of decoupling capacitors.
Example at DC Vout of SMPS or LDO regulators. Does it really matter which capacitor out of 100nF, 1nF and 10uF is placed ...
- 59
0
votes
0
answers
127
views
Techniques for measuring the ripple current of SMD electrolytic capacitors
I am currently creating a test plan for an AC/DC converter (90VAC...264VAC -> 12VDC) I've been working on. Since the output electrolytic capacitors are of SMD type, I am trying to come up with ...
- 3,589
0
votes
1
answer
70
views
Series capacitors; negative voltage
Interesting observation today; I set up a series stack of 4 cheap electrolytic capacitors (10V 220u) and after about 5 mins of applying 30V the lower most cap had settled at -300mV. The other three ...
- 93
0
votes
1
answer
94
views
Chargng Capacitors in series
I am trying to build a capacitor bank for a project in order to feed an inductor with "high" voltage(500V) however I only have a dc generator rated at 100V at my disposal. Charging 5 identical ...
0
votes
0
answers
510
views
Serial DC-link Capacitor to increase the effective voltage rating
I am developing a 2-phase motor driver system, which requires my inverter's DC-link to be near 480V. 480V is used to generate 2 line-line voltage of 220Vac(using 3-phase inverter).
The Aluminium ...
0
votes
2
answers
125
views
What is the capacitor needed for 30 kHz power rectifier?
I need to rectify 200 V at 30 kHz for a resistive load of 3-4 kW. I use a 1200 V/60 A Schottky diode bridge. I have some 6800 uF/450 V capacitors. Can I use them, or should I use other values? Is ...
- 1
-1
votes
1
answer
106
views
If I added a Capacitor to this circuit would it charge both and would the charge led still work?
If I were to add a second capacitor to this circuit of roughly the same capacitance (120uf). Would this circuit charge both up completely, and would the LED still accurately depict if the combined two ...
- 61
-1
votes
1
answer
361
views
How to size a capacitor?
I want to design a PCB with some ICs and I've read that it's recommended to use decoupling capacitors to filter out voltage spikes. There are three ICs on the PCB: Arduino NANO, nRF24l01 module and ...
