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

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14 views

Need To Understand Transistor Based Led Circuit

Which Transistor Topology Is Used in the Below Circuit & Why? Need to understand the purpose of zener diode (ZD2) with 12.5 Vz and R1 with 2k value? Why C1 & R2 is used for Q1 transistor? ...
0
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1answer
57 views

What is the purpose of resistance & capacitance in parallel to Load ( refer ckt )

What is the purpose of resistance & capacitance in parallel to Load ( refer ckt ) ? As per my understanding these capacitor & resistor is for filtration purpose ( kindly clarify the same) . ...
0
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1answer
70 views

Calculate the impedance and phase angle of a capacitor

I’m trying to calculate the impedance and phase angle of a capacitor in software for a microcontroller project I’m working on, and I’ve included a pic of what I mean (not to any scale). I’ve ...
1
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2answers
25 views

RC High Pass Filter output drift problem

I am unable to find a proper explanation for this. When I create the passive RC circuit as shown and feed it 8 us pulses at 25KHz, The output of the RC circuit drifts for some time until it settles as ...
0
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1answer
61 views

Problem with high-pass filter - signal gets shifted down

I have a problem where I am passing pulses received from a photo-diode into a high pass RC filter. Circuit shown below. The pulses are being received at 25Khz. Before the filter, the pulses are ...
3
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0answers
31 views

Unknown resistive disk in parallel with AC motor capacitor

This assembly is the motor connector for a Grundfos U15-38SPA circulating pump, which interfaces to the capacitor (2uF) and power supply (220VAC). Between the two brown wires leading to the cap is ...
0
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4answers
81 views

Using a battery charger instead of a battery?

I have built a simple circuit with two diodes that light up intermittently. It requires 9V DC voltage to run. I don't have a DC source at home, and would like to avoid buying 9V batteries repeatedly ...
0
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2answers
157 views

Can I use 250μF capacitor instead of 100μF?

I am trying to drive a stepper motor from an old DVD drive with the Pololu A4988 driver and an Arduino. The data sheet says I need a 100μF capacitor to prevent voltage spikes when using a 12V PSU (I'm ...
0
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3answers
59 views

Why do smd components in eagle have padding?

I'm new to eagle and I don't understand why there is a small padding to the left and right of some SMD components (for example the 0402 cap in the image). Having the physical board in my hand ... ...
3
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3answers
90 views

Charge on capacitors

If three identical charged capacitors get connected in series to each other (there is no battery). How would the charge distributes itself among them? Are they in series? Or two capacitors are ...
3
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1answer
43 views

Can we determine if a filter is butterworth or chebyshev from its physical topology?

Can all analog filters be classified as Bessel, Elliptic, Butterworth or Chebyshev? Given a physical ladder topology of several stages of {L, C or LC} in {series or parallel}, is it possible to ...
0
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3answers
95 views

Why does an uncharged capacitor short out a resistor in a basic DC circuit?

I’ve really only dealt with two laws thus far concerning circuits and capacitors: $$V=IR$$ $$Q=CV$$ The first obviously being Ohm’s law and the second the equation for a capacitor’s charge. I’ve seen ...
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1answer
68 views

Electromagnet circut with backup capacitor to keep metal object on roof of car whilst driving [on hold]

I need a little help with an experiment. I am trying to attach a metal sign to the top of a vehicle using electromagnets. The idea is that we will place two electromagnets one at either end of the ...
0
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1answer
20 views

Calculate capacitance i.a. via reactive power

The ampermeter of the following circuit shows 10A (AC) and the voltmeter 220V (AC). Furthermore its known that: $$ cos\varphi=\frac{2}{3} \\ f=50Hz $$ I calculated the following: $$ ...
1
vote
1answer
69 views

time it takes for the voltage to achieve 7 V

C1 = 56uF C2 = 12uF R = 12kohm E = 13 V I have this circuit and I want help to find out how long in takes for the voltage Uc2 to achieve the value 7 V? I have calculated the time constant to 117 ...
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0answers
50 views

Dicharge a Photoflash Capacitor in a coil

I am trying to do the coin tosser according to this pdf (result here) So the circuit is supposed to be this one: simulate this circuit – Schematic created using CircuitLab However when ...
0
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0answers
48 views

How do I solve first-order circuits?

I'm having a lot of trouble understanding this topic in my circuits class for some reason. Take for example this circuit, I'm told that \$v_{1}(t)=10\$ and \$v_{2}(0^{+})=10\$ volts. I need to ...
0
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2answers
20 views

Step Response RC Circuit: Current at Capacitor

I have a problem understanding why is that ic=0 at t<0 if the switch is closed for a long and only opened for t=0? My friend told me that at t<0, the ic will always be 0A regardless whether ...
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1answer
57 views

capacitor charging to over specified voltage

Can i charge in real circuit any capacitor, that is rated to 2.7 V to input voltage 12 V as shown in the picture? I mean regular charging and discharging. The current through capacitor will never ...
3
votes
2answers
71 views

Calculating the capacitance

I have a problem that I would like to have help with. In the image above I need to calculate the capacitance. The values I was given in the beginning was: So I calculated U3, which was 17.3 V ...
9
votes
1answer
1k views

Capacitor discharging theory vs experiment doesnt match

I am trying to discharge my 1F capacitor over a 47 ohm resistance which i connected in parallel with the capacitor . İ have calculated the time it would take to discharge from 5V to 4V as 10.55 ...
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0answers
51 views

What is step discharge with capacitor

So I was learning about capacitors and I was analyzing the voltage with a Saleae Logic analyzer when I noticed something strange. When I discharge the capacitor and I zoom in on the recorded data, ...
0
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2answers
50 views

Op-Amp decreasing amplitude of audio signal

For a final project for an electrical engineering course I am taking (my first), we have been tasked with combining input from a small microphone and an aux cord, amplifying it, transmitting it via a ...
0
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2answers
39 views

Purely Capacitive AC - voltage and current relationship

Studying electronics, capacitors in AC circuits currently. Can not understand two formula's. I see it stated as fact: "In purely capacitive AC circuit Current leads Voltage by 90 degrees." I ...
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1answer
44 views

What is a capacitor ripple current?

Suppose I have a simple full wave bridge rectifier, with resistive load. Is capacitor ripple current a charging or discharging current? Or maybe it is an avarage/RMS of any current flowing through a ...
0
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1answer
62 views

How critical are the input and out capacitor values in a linear voltage regulator?

7805's datasheet recommends a 0.33uf and a 0.1uf capacitor for input and output respectively. For a clean input voltage and a resistive load, I've used this kind of regulators without the ...
0
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1answer
37 views

What is the best method to determine bypass capacitors for each chip in Mixed-Signal Systems? [closed]

In datasheets of chips, usually they have reference designs and to those designs bypass capacitors are predetermined. But, when I examine some high level designs of those chips I see different bypass ...
2
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0answers
34 views

How to connect capacitors to SIM800C gsm module [duplicate]

I am powering a SIM800C from a 3.7V Li-ion battery. If the battery charge drop below 85% (it still has 4.1V measured without load), the module keeps restarting during startup. This probably happens ...
4
votes
1answer
92 views

Alternatives to motorized variable capacitor?

I want to dynamically fine-tune the capacitor (about 100pF) of an RLC series resonant circuit, so as to keep it tuned despite variations of the coil's environment. Operating frequency is ...
7
votes
3answers
541 views

Chokes vs. small capacitors on signal cables

I know that many signal cables (usb camera to computer cables, etc.) have bulky ferrite chokes on them to prevent noise. Why do they all have ferrites instead of ceramic capacitors? Small ceramics ...
2
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3answers
46 views

Does the physical size of electrolytic capacitors affect how they perform?

I have two 100uF electrolytic capacitors. Same voltage rating and same temperature rating, yet one is 8 times larger than the other one, being 2x longer and having 2x the diameter. If I want to use ...
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1answer
58 views

Finding inductor current at infinity

Can someone please explain how to go about solving this? I understand how we obtain Vc but when looking for the inductor current at infinity I get confused. Thanks!
2
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5answers
237 views

What is meant by “capacitors try to try to maintain voltage at a constant level”

I'm trying to self learn electronics and to that end have been studying capacitors and I came across the following A capacitor’s ability to store energy as a function of voltage (potential ...
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0answers
64 views

Good or bad capacitor

iv got an electric fencer im looking at the the output is only 600v on the secondary side of the transformer, it should be 6000v. I am just looking at the pulse capacitor to check the health of it. It ...
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3answers
41 views

Voltage across Capacitor and Inductor with DC Voltage and Current source

As we know, capacitors and inductors are most important components in circuit design. I am just curious about how they will behave when connected across voltage or current source as per below image ...
1
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1answer
45 views

What are the capacitor values and why there are holes in PCB? - Semtech's reference design - SX1272MB1DCS

Semtech is providing a reference design concerning the SX1272 chip: SX1272 modules: SX1272MB1DCS - 868 MHz - Combined RFI and RFO, switchless (Ref design only) I can't find the values of C12, C14, ...
0
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1answer
57 views

What happen if i connect the capacitors with few LED Strip in parallel?

I want to make my LED Strips which connected in parallel to dim out slowly. Therefore, i thought of using few capacitors (in parallel) to make this possible. if i"m using 12V batery as power supply ...
3
votes
1answer
135 views

Dimensioning smoothing capacitor for China DIY LED lamp

My first question here so bare with me if I'm a bit "off" or so regarding the level of knowledge etc. My purpose is to try to learn things. So I started off by buying some LED lamp DIY kits of this ...
0
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3answers
46 views

Voltage graph of capacitor with AC source

below is the 'Dickson's charge pump'. What I want to know is that when clk is on, why does Vx is 3v instead of 1v? I just thought Vin contribute 2v to cap, clk contribute 1v to cap, so 2v - 1v = 1v ...
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1answer
69 views

Expanding on Arduinos definition of a capacitor

This oversimplified explanation is somewhat confusing and I haven't been able to fully understand what they are trying to say. They already seem to be talking about AC and Voltage regulation. ...
3
votes
1answer
214 views

MSP430 launchpad's bypass capacitor mystery!

I've been looking into MSP430 launchpad's schematics and saw something that can't quite understand: the bypass capacitors for the reset button and for the P1.3 are different (1nF and 100nF ...
3
votes
3answers
59 views

MIL-Spec Differences

Recently I was following an online project guide, and ordered many components online. One of the components, a 0.10uF capacitor with 50V rating, returned some results which said they were "MIL" ...
0
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4answers
119 views

Possible error in schematic; unrealistic capacitor

I am trying to get the parts for this electromagnetic coilgun, and I have gotten almost all of the parts. I cannot seem to find the 1,000 uF 1.5KV capacitors (C3 and C4) for the voltage ladder, and ...
2
votes
3answers
122 views

How to lengthen a short pulse?

i'm building a shot counter circuit for my airsoft gun controlled by an ATtiny26L MCU, where the shots are detected by an infrared diode + phototransistor couple. The PT outputs positive signal when ...
0
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1answer
34 views

Capacitor Sizing for A Full Wave Bridge Rectifier?

Building my understanding of the issue from (First PSU - need help with capacitor size) (especially the comments/ripple wiki/several capacitor sizing webpages) the calculation for rectifying a full ...
0
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1answer
122 views

electronics testing capacitors

I am trying to come up with the equation for testing electronic capacitors by discharging them with a test pulse using a known resistor value. A known value resistor is switched in circuit for a test ...
0
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3answers
64 views

What makes the charge on a capacitor change?

I have just realized that I actually do not have a through understanding of capacitors and hence, I am asking this basic question. I was trying to understand how an astable multivibrator works using ...
0
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3answers
49 views

Capacitor behavior on collector of a BJT?

In this circuit: simulate this circuit – Schematic created using CircuitLab As soon as power on, the transistor will start conducting in saturation. This will make V1 ~ 100mV (\$ ...
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0answers
42 views

bernina motor capacitor exploded. How to repair motor [closed]

My girlfriends Bernina sewing machine exploded and catched fire. It made a lot of smoke, probably wasnt very healthy. Now what the bernina store said was to get a replacement motor but that also means ...
4
votes
2answers
42 views

Capacitor Balance Resistor value

If you help to find out the right formula to calculate Balance Resistor and its power value( R1 and R4 ) as shown in Pic. because i have seen every one is using different different formuals. Data ...