Questions tagged [capacitor]

A fundamental electronic component that stores energy in an electric field, commonly used in filtering applications.

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1answer
85 views

Is the dipping in VCC caused by inrush current of charging 1 uF and 0.1 uF capacitors?

I'm powering MSP430FR5994 microcontroller from a power supply using a 2.2 V regulator. This regulator can source up to 200 mA. When MSP430 turns on, it starts to charge a 1 uF and 0.1 uF by driving ...
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2answers
113 views

The force in Coulomb's Law of Electrostatic Forces seems really high

I am reading Radio Shack's Basic Electronics, and it presents Coulomb's law of electrostatic forces: $$F=k \frac{Q_1Q_2}{S^2}$$ and they say k is \$9\text{x}10^9\text{ newton meter}^2/\text{coulomb}^2\...
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2answers
158 views

Detect the existence of 1 uF bypass capacitor through VCC & GND testpad

I have a very simple circuit as above, there is a 1 uF bypass capacitor connected parallel to the VCC & GND of the IC. I need to detect the existence of this capacitor through the testpad, but my ...
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2answers
110 views

Buck converter waveform

It became very hard for me to understand the concepts associated with buck converter waveform. What is the role of capacitor in its output terminal? Is it used for smoothing the voltage ripple? Why ...
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1answer
45 views

TRIAC Voltage Control

I have the simple Triac voltage control circuit. The values of resistance and capacitor are 10k and 0.1uF respectively. I want to know that the following. 1- How can we calculate these values of ...
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1answer
143 views

Why did my capacitor explode? [closed]

I'm new to electronics and am trying to use an Arduino and 2 BTS7960s to control 2 motors. I am powering the circuit with a 20V max Black and Decker battery. Here is what the motor part of the circuit ...
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2answers
61 views

RC Discharge (Natural Response) Currents

I'm a complete rookie in the world of electrical/electronic engineering so please excuse the potential stupidity of the question since all the resources I looked at didn't even feel the need of ...
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2answers
70 views

Help with aluminium capacitor identification

I bought a lenovo i3 mini desktop and it turned up very badly packaged and rattling inside. I was allowed to keep it so decided to take a look inside and everything appeared fine apart from one ...
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0answers
42 views

Y capacitors in surge suppressor in a TN-C-S system

"Surge Protectors", "power strip", etc. I noticed many of them have Y caps (line-earth/neutral-earth) usually 102 or 222M Y safety caps to filter line and earth neutral and earth ...
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22 views

Ceramic Trimmer Capacitor Dielectrics

I can't seem to find much information on the dielectrics used for ceramic trimmer capacitors. Such as the Knowles JZ150HV. What kind of dielectrics are normally chosen for ceramic trimmer capacitors? ...
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2answers
92 views

Replacement of a ceramic smd capacitor without diagram or screen printing

I was tasked with trying to repair a Samsung motherboard from a NP740u3M laptop with a BA92-16998A model board, a drink has been spilled there. It is a fault of ceramic smd capacitors. I'm looking for ...
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2answers
53 views

Reason for using short leads with capacitor tester?

When I was a high school freshman many moons ago, I took an electronics course. When the instructor introduced capacitors and how to test them, we used meters that had very short (3 inches or so long) ...
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29 views

Bias tee for floating DC supply

I have a floating DC low noise current source driving a load. I also need to drive this load with an RF source but the grounds are not referenced to each other so I don't think I can use a standard ...
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1answer
73 views

How will this circuit work [closed]

This circuit is after the rectification process how will this work
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2answers
1k views

What is the purpose of this extra capacitor in a notch filter?

I understand notch filters, I can write transfer functions and draw Bode diagrams to see how they work. As far as I know, the notch filter only has: C1, C2, C3, R1, R2, R3. The schematic I have here ...
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2answers
83 views

What happens when a capacitor sees a change is its resistive load, under constant current?

simulate this circuit – Schematic created using CircuitLab Suppose the capacitor is fully charged at t < 0 s, so the current through C1 is 0 A, and the voltage across its terminals is I * R1. ...
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1answer
70 views

Transmission Transfer Duty Solenoid Hack; TCU Dummy Load Heat Management & Relay Debouncing

Rev A I have tried to properly incorporate the things you outlined in the comments Tony. Honestly a lot of what you said went over my head and required some additional reading before I could respond. ...
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3answers
140 views

Audio amplifier - input stage, negative feedback and current limit

I am reading Audio Power Amplifier Design by Douglas Self and have a couple of questions. With no input signal, (Q2 base = Q3 base = ~0V) no current Ivas should coming out of the long-tailed-pair (...
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2answers
2k views

Why can't the LED flash for a while?

I am new to electronic circuits. I made a circuit as this picture shows: I want the LED to flash for a while when the switch is open, but it seems the capacitor doesn't do its job well. power source ...
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2answers
102 views

Exceeding maximum capacitive load of isolated DC/DC converter

I have never needed to exceed the capacitive load limit of a DC/DC converter before, but I need to for an upcoming application that demands a very low power supply impedance. I believe this is a ...
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3answers
70 views

Schematic notes: Place capacitor as "close" to pins: Is this a necessary note? Is it a significant point?

Background I am building a ATMega4809 board that allows the board to be programmed using the Arduino IDE. While examining the following schematic I noticed that where the caps are placed the author ...
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1answer
70 views

Help please identifying these components and their use

My first post, and I know very little. I have acquired a very old watch cleaning machine, its basically an electric motor that spins a small basket. I'd dearly love to get it working and have started ...
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5answers
1k views

How to calculate values for decoupling capacitors

For decoupling we just use a capacitor like 1 uF bulk and 0.1 uF ceramic caps at each power pin. But how are these values calculated? How many caps do we need to use in parallel? Can anyone explain it ...
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4answers
110 views

How does current flow through a battery in a battery-capacitor circuit?

I am taking the Coursera course on DC linear circuits and have various questions in parallel. I found the 80% related question "How does current flow through a voltage source" and my ...
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1answer
88 views

Why there is capacitor in series in high speed designs like SGMII?

Why we are connecting capacitor in series in high speed designs like SGMII. If it is to remove DC voltages, why we are not using on other signals like I2C, SPI and so on. What is the major purpose. ...
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1answer
38 views

Lser of capacitor not equivalent to a separate inductor in LTspice?

I just noticed a strange issue in LTspice and I am wondering what I am doing wrong. This is about capacitors with series resistance and inductance: Example 1: A simple bandpass. Behavior seems ok. ...
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4answers
486 views

Output capacitors of DC-DC converters

I am trying to understand what type of output capacitor is a better option. Suppose I require a 10uF output capacitor at the output of the buck converter, which one should I pick - aluminum ...
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0answers
79 views

Right capacitance for a capacitor parallel over power output?

I am building a self playing piano. I daisy-chained 11 74hc595 shift registers to control (11*8) solenoids. (figure 1 only shows 1). The solenoids are rated at 2 Amps each. I use SPI from the arduino ...
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2answers
117 views

How to slow down an AC fan

I have an AC fan rated at 220 V, 50 Hz, 12 W. It's too noisy so I would like to install a capacitor in series to slow it down. I don't know how to calculate this. What size capacitor is approximately ...
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3answers
179 views

Voltage/Current phase shift caused by capacitor/inductor

Im trying to understand exactly how a capacitor and inductor affect the RC and RL circuits and am not sure exactly what is correct. When I look online for phase shifts for these components it mostly ...
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1answer
167 views

Capacitor frequency response

I am graphing a 1 uF capacitor's frequency response in a circuit like the one below with a 100k ohm resistor. I am using a 10V (peak to peak) sine wave as the input. I've calculated the -3 db down ...
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0answers
32 views

3D FEM Vector Potential Formulation Formulation

Most freely available FEM analysis software for induction machines seem to only be able to simulate 2D machines without circuit coupling. I have attempted to formulate the problem of a capacitor run ...
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5answers
222 views

RC peak detector calculation

Before the edit was made I have a signal that is an AC signal and I would like to track its envelope. I'm not doing AM, I'm trying to make a transducer for my sensor. Frequency is constant but ...
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1answer
53 views

Is using an over voltage rated capacitor going to work equivalently in this circuit?

Total noob at electronics, apologies if this is a daft question. Circuit picture is here which is a RFID module, but in my case connected to an Arduino Nano rather than a USB dongle. I broke the 10 V,...
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1answer
40 views

Finding the Gain Equation of a Boost Converter with LC Resonator

I am trying to implement the following datasheet circuit in a project. The circuit is a boost converter with an LC circuit resonator (L3 and C4 resonate). I am trying to find the DC transfer function ...
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2answers
88 views

Need values for capacitors and resistors [closed]

I have experience reading schematics for making guitar pedals, but never designing a project from scratch. I have a 12V 4A battery powering a cooling element (12V TEC1-12710 Thermoelectric Cooler ...
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1answer
59 views

RF ground capacitor broken off on Raspberry Pi 4 - How does it affect performance?

Observe the following image: A small SMD capacitor near the J4 display connector has broken off on my Raspberry Pi 4 Model B. WiFi appears to function normally on the 5GHz band, but I'm very curious ...
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2answers
138 views

Why do we have exactly three parameters to describe relationship between current and voltage in linear elements?

I was simply pondering over everything I learned about circuits and electricity and there was this one question I couldn't give a simple answer to. Why exactly do we need only these three parameters ...
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2answers
83 views

Flyback diodes instead of a resistor in series with a capacitor in parallel with the inductor

Why do people use flyback diodes instead of a resistor in series with a capacitor in parallel with the inductor? Wouldn't it be just as good? It would also have the benefit of working with motors that ...
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6answers
762 views

Differentiator and integrator - without op-amp

I am trying to understand the working and function of the integrator and differentiator circuits using op-amps. Can someone tell me why we need to use op-amps for that function? Selecting just the ...
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3answers
73 views

Behaviour of a capacitor in a load powered by a constant current source

It's said that capacitors are open circuits when there's a constant current, but it's also said that capacitors resist a voltage change. So which of these two holds true in the scenario I described in ...
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1answer
60 views

Building intuition on the behavior of inductors and capacitors with both voltage and current

I understand that an inductor cannot change current instantaneously, however I am not sure how that relates to the voltage. In a high pass RL circuit, for example, I know that the inductor presents a ...
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1answer
47 views

Shouldn't the Thevenin equivalent have the same behavior (regarding the transfer function) as the circuit it's derived from?

I am new to electronics and I have a little trouble applying the basics I learnt so far. My problem is basically that I don't understand why we consider the second circuit below as the Thevenin ...
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1answer
31 views

Automated toggle circuit

I'm trying to build a automated toggle circuit which toggles in a certain frequency determined by an RC time constant. I made a circuit which i planned to toggle between 5V and transistor saturation ...
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0answers
21 views

How to include capacitor ESR frequency dependence in simulations?

The exponential current decay of a charged capacitor with external (constant) resistor is well known. However, I am trying to simulate a capacitor charge/discharge with only the capacitor ESR as the ...
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2answers
112 views

Capacitor voltage function

How would you find the mathematical function of the voltage discharge curve for a capacitor considering the following circuit and conditions: When time t=0, the capacitor is fully charged with the ...
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1answer
52 views

What is the correct way to solve this DC RLC circuit?

I am studying for the FE Mechanical exam and am working my way through the electricity & magnetism section. Attached is a practice problem statement I found online and am having a bit of trouble ...
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1answer
51 views

Problem in capacitor selection

The SIM800L datasheet suggesting a low ESR capacitor for providing a 2 ampere burst current during data transmission. According to this site MLCC provides the lowest ESR at high-frequency application, ...
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2answers
229 views

How can the amount of dielectric material affect a PCB?

So I understand that the dielectric material on a PCB (i.e. FR-4) can affect the capacitance of the board. The thinner the material, the larger capacitance between the layers on the board. What I don'...
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0answers
38 views

What does the electrolytic capacitor specification E 9 A 105 CF mean?

What do these electrolytic capacitor specifications mean? E 9 A 105 \$^\circ\$CF Is its maximum temperature 105 Celcius or 105 Farenheit? It has both letters.

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