A fundamental electronic component that stores energy in an electric field, commonly used in filtering applications.
-3
votes
1answer
70 views
can capacitor increase flow/quantity of water in water pump [closed]
can capacitor increase flow/quantity of water in water pump. we are already using capacitor of 25 uf. can water quantity be increased if we use capacitor of 30 uf or any higher which u suggest.
-5
votes
2answers
69 views
How does the 555 timer IC circuit work?
As a beginner to electronics I'm having a tough time understanding circuits that have a combination of different components, including the following timer circuit. Its based around a LM555 timer IC. I ...
5
votes
2answers
112 views
Will LEDs in opposing directions be damaged?
I was trying to build a simple RC circuit that causes an LED to fade in and out. However, I have electrolytic capacitors, which means that they have polarity.
If I connect a circuit as follows , is ...
5
votes
3answers
171 views
Ceramic vs. Film Capacitor: Which one is preferred in audio circuits?
I'm considering building an amplifier following instructions from a MAKE magazine article.
However, as I was reading the circuit schematic, I noticed that the author denotes that the capacitors C101, ...
6
votes
6answers
389 views
Basic Electronics - I want to learn the “why”, not just the “how” [closed]
I have been looking for a very basic book on electronics, but many of them explain what the components do (and how they are made) and then go into designing circuits that do stuff. They tell you to ...
2
votes
1answer
81 views
Two questions, caps again
If I discharged my caps on thick bronze rails connected to the caps by copper wires and nothing else, would that be dangerous? I'd like to safely discharge the caps as fast as possible for the ...
6
votes
3answers
226 views
How does this circuit diagram work?
I don't understand this circuit diagram here, but I'm sure that you can help me out.
I'll explain what I have figured out so far.
EDIT: It's a metronome circuit. Sorry for being unclear about that.
...
2
votes
3answers
103 views
How exactly does switched capacitor system work, what exactly is the detail of the primitive that switches
I have been seeing these switched capacitor circuits for some time now and have even seen Z-transform being used to model how these circuits behave. While I can see that there is some capacitor that ...
2
votes
2answers
97 views
Are additional smoothing capacitors required off of a voltage regulator
This is a subset of a circuit I am building to run motors off a PIC 16F884:
simulate this circuit – Schematic created using CircuitLab
I noticed last night as I was drawing up my ...
1
vote
2answers
52 views
How to use integration or differentiation to optimize frequency in achieving a specific phase angle?
Question:
With source voltage kept constant at 8V peak to peak vary the frequency until the phase angle "theta" Vr referenced to Vs is approximately 45degrees. Record the Vpp value across R1 and the ...
0
votes
1answer
125 views
Capacitors and capacitance
this time I'd like to ask a few questions about capacitors, all noob questions again;
What's a better idea, having one capacitor at 5x farads or five capacitors at x farads each? I want to get a ...
-3
votes
1answer
102 views
I want to build a portable railgun and I'm a complete rookie [closed]
I'd like to enter the world of electronic hobbies by making a railgun, and so far I know that I understand the basics of the device and that I need high amounts of direct current.
However, I am ...
0
votes
2answers
79 views
RC circuit and tone
Can I generate a tone on an 8-ohm speaker using a 5VDC power source, resistor and capacitor? For example if I want to generate a 440 Hz tone, could I use resistor capacitor values such that RC = ...
2
votes
3answers
64 views
Trigger Monostable 555 When Capacitor Raises above 0.5 Volts
So I want to trigger a monostable 555 to fire when a capacitor raises above 0.5 volts. My plan was to use a Zener diode to bias an NPN transistor that would trigger the 555. But I discovered the ...
4
votes
4answers
139 views
Would a capacitor labeled 470K be 47pf or 470pf
I have a cap labeled 470K. I would have thought for sure that it would be 47pf until I saw this link where it said if a capacitor has a 0 as the last digit, it is the whole thing in nano-farads. How ...
1
vote
1answer
90 views
Zener doesn't seem to be working
So I'm trying to use a zener diode to limit the voltage across a capacitor - specifically, to 2.2V.
As you can see, I'm using a 9v supply. The zener is in series with a resistor - either 100 or ...
3
votes
1answer
117 views
At what frequency will the reactance of a 1μF capacitor equal to the resistance of a 2kΩ resistor?
Here is my work:
\$ R = 2000 \Omega\$
\$ X_L = 2 \pi f L = 2 \pi (1 \mu F) f = 6.28\mu F(f)\$
\$f = \dfrac{2000 \Omega}{6.28 \mu F} = 318.471MHz \$
Does this look right to everyone?
16
votes
7answers
1k views
Why do capacitors lose capacitance in series?
Unlike rechargeable batteries, capacitors have a lower capacitance in series. Why is this and if I charge each cap separately and then put them in series, will it still be a lower capacitance?
0
votes
0answers
44 views
How to connect a 20 uF motor run cap & 27K Ohm resistor in parallel across 2 blades of a wall plug enclosure?
My project is to connect a 20uF motor run film capacitor PLUS a 27k Ohm resistor IN PARALLEL to an AC wall plug enclosure (2 prong plastic by Polycase).
The cap is a Panasonic JS18206-AA film with ...
3
votes
4answers
167 views
Can I replace a SMD capacitor with a wire
I have a cheap device, which has blown one of its SMD capacitors (no markings) and I was just wondering that what will happen if i remove the cap and put just a jumper wire to its place?
6
votes
2answers
180 views
Inductor equivalent of capacitor's charge
Because inductors share similar equations in their charging/discharging cycles, I am wondering if inductors have something like charge.
Capacitors have capacitance and charge while an inductor has ...
5
votes
4answers
277 views
Transistor Delay
I'm attempting to make an alarm for a freezer so that if the door gets left open, after 1 minute or so, an alarm will sound.
I've got something similar to the schematic below. When the switch is ...
-1
votes
0answers
45 views
Problem with simple RC oscillation circuit
I tried to follow this simple RC oscillation circuit:
I connected a 470 Ohm resistor (say R1) and a 10 uF capacitor (say C1) in series and from the negative end of the C1 cap I attached another 470 ...
4
votes
2answers
99 views
Why does the led turn dim gradually and then turn off when attached to a capacitor in series?
I connected an LED in series with the capacitor (any type of capacitor. I used one of 10 μF) and connected them with the 9V DC battery. I connected the positive pin of the capacitor directly to the ...
1
vote
1answer
61 views
Values of capacitors [duplicate]
I'm sorry if this has been asked, as it's a simple question, but I haven't found it.
Is there any reason why capacitors are built in so fixed values? For any other components the manufactured value ...
1
vote
3answers
116 views
Charging a low-voltage high-C capacitor. Efficiently
I'm currently upgrading my wind-up torch - upon opening it, I found the manufacturers had been quite sneaky in that the circuit is EITHER windup OR battery powered - worse, the batteries are ...
4
votes
3answers
119 views
Charge discharge curve of a capacitor, Arduino
I'm trying to visualize the charge discharge curve of a capacitor with Arduino. This is my curcuit:
simulate this circuit – Schematic created using CircuitLab
13 is pin 13 of the Arduino ...
-6
votes
0answers
75 views
How to charge a 2.5 volt SuperCap [closed]
Can I just use 2 double A's to charge a 2.5 volt 150 farad supercap, or will it break? Is there a simple circuit or something?
4
votes
3answers
234 views
How long would a 150 Farad Capacitor light up an LED
I have a bright white LED from a flashlight. Aproximatley How long will it light up with a 150 farad 2.5 volt capacitor. Do I need a resistor? And if so how many Ω? The capacitor is a maxwell 150 ...
1
vote
1answer
113 views
how to select capacitor values
I am trying to find information on formulas used to calculate capacitance required for a given circuit. Not a circuit in particular, just in general how to figure out what value should be used. I know ...
2
votes
2answers
77 views
How can I find the voltage rating for a particular ceramic capacitor?
I have an old tube radio. There is a ceramic cap with:"RMC / 0.1 / 1400V / Z5U " written from top to bottom, respectively. Now, this cap has broken at it's base and can't be resoldered and so must be ...
2
votes
2answers
87 views
What is the capacitor charging time when charged with a pnp current mirror circuit?
I want to use a 555 in monostable mode to make a ramp signal generator. The capacitor would be charged using a current mirror circuit.
Given a input voltage, what would be the charging time of ...
2
votes
1answer
71 views
Placing component vertically in ISIS
I am using a large capacitor in one of my circuits and due to space constraints I can't keep it in the vertical position. Does anybody know how I can place it horizontally in the circuit in ISIS?
2
votes
4answers
270 views
Why can I put an electrolytic capacitor on AC?
I have seen here and there schematics with electrolytic capacitors put on AC. And this sounds weird to me.
Electrolytic capacitors have a polarity, right? If we invert the polarities on DC, bad ...
5
votes
4answers
253 views
How the capacitor works (in a debouncing circuit)?
On the following circuit ( a debounced push button that turn on a LED ):
simulate this circuit – Schematic created using CircuitLab
I'm trying to understand how come the LED will not ...
1
vote
1answer
80 views
Using capacitor to maintain current flow past opening of switch
This circuit turns on the motor when something blocks the beam from the LED to the phototransistor. I want the motor to remain on for 5 seconds after the beam stops being blocked (i.e. from when the ...
-3
votes
1answer
56 views
Calculating the voltage across the capacitor and the energy lost in an RC circuit [closed]
A circuit is shown in the figure above with \$R = 22 \Omega \$ and \$C = 10 \mu F.\$
The switch \$S_{1}\$ is closed at \$t = 0\$. The initial voltage across the capacitor is \$V_{co}.\$
What is the ...
2
votes
1answer
106 views
Calculation of cutoff frequency in larger circuit
I'm having some difficulties choosing appropriate resistors and capacitors to get specific cutoff frequencies. I guess it's because I'm just considering the single pole components rather then the ...
2
votes
2answers
144 views
2kV capacitor on ethernet?
I'm building the circuit of this article:
C7 is rated 1nF 2kV. Is this right, does this capacitor need to be able to handle 2kiloVolt? Why is that? Is ethernet dangerous?
2
votes
2answers
52 views
Simulating AC-Coupling capacitor used in PCIexpress
I am trying to simulate and understand the AC-Coupling capacitor effect on signals with DC bias.
I have a signal which has excursions between let's say 0.5V to 1.5V, So, it has 1V(0.5+1.5/2) DC bias. ...
0
votes
2answers
85 views
damaged capacitor and/or power amp
I have a Mackie MR8 MK2 powered studio monitor that recently started making a horrendously loud humming and clicking noise (I mean LOUD, as in cover your ears). Being just out of warranty, I decided ...
2
votes
1answer
81 views
Switch from electolytic to ceramic capacitors in car ECU?
I'm looking into replacing the capacitors in the vehicles ECU. I know the ratings and voltages for the three. My question though is which would be better to go with, electrolytic or ceramic. I'm not ...
0
votes
1answer
264 views
Water level: BIG capacitive level sensor with steel bars?
So I want to measure water level under a bridge, or inside the city drain.
Would it be possible to run two long (4 meter) metal probes, each one enclosed inside a PVC pipe, and placed one next to the ...
2
votes
1answer
286 views
Mystery circuit: latching relay control with transitor / capacitor - why doesn't it work?
I've been looking for a way to control a latching relay with a microcontroller that doesn't quite have enough current on the output pins to operate it directly. I found this intriguing circuit using a ...
0
votes
1answer
45 views
What is the principle of active voltage balancing/equalizing device?
I am wondering about active voltage sharing devices. Their purpose is to equally divide voltages on slightly unequal super-capacitors. I found some papers like this, but it is too scientific.
I want ...
7
votes
3answers
190 views
What elements of a capacitor make it higher voltage and higher capacitance
I know capacitors have 2 plates, and an insulator in between the plates. I am wondering what elements inside of a capacitor make the capacitance larger, and what makes the maximum voltage higher?
3
votes
2answers
134 views
What's wrong with this Phase Shift Oscillator?
I am trying to design a phase shift oscillator, using a CE Amplifier.
I have a Vc of approximately 6V, gain of approximately 40(>29, as required).
I aim for an oscillation frequency of 1.5 kHz.
But ...
1
vote
3answers
81 views
Identifying SMT element 331K
I am trying to repair a remote from a car lock. The symptoms are that a red led is lit longer than usual after button press and no respond from car lock. It works sometimes. The battery and ...
2
votes
2answers
100 views
Planning of integrator and derivator circuit
I have to plan a circuit given by the series of an integrator and a derivator circuit. I haven't planned a circuit before, so I ask you if my reasoning is correct.
The only condition that I have to ...
1
vote
1answer
111 views
We want to generate a spark suitable for igniting a potato cannon (alchohol class fuel) preferably without automobile-class coils
I assume we need about 1000v for a 1mm gap. I have a coil about 2cm with an iron core, but no idea how big L is. I have a lot of 330uF capacitors rated for 200v.
What would be a clean way of doing ...
