A fundamental electronic component that stores energy in an electric field, commonly used in filtering applications.
1
vote
1answer
29 views
What are the functional differences between monolithic and disc ceramic capacitors?
I've inherited an older part numbering scheme, in which ceramic capacitors are divided into disc and monolithic types. Is this actually a firm division in their characteristics? If so, what are the ...
-4
votes
0answers
38 views
Energy Meter Supply Designing based on super cap [closed]
I have an energy meter LPRF based on SMPS power supply. I want to change my power supply to CAP Drop. Chossing a SMPS supply is that my module needs more current approx 70mA for comunication which is ...
1
vote
3answers
126 views
What components can an FPGA replace/emulate?
I've been under the impression that FPGAs were merely, well, field-programmable gate arrays, but I've seen some example schematics with resistors, capacitors, and such in them. As such, can an FPGA ...
0
votes
1answer
74 views
Flyback transformer
Recently, I posted a question about a flyback transformer schematic I was having.
If you didn't check the link, I was having problems with the frequency of the 555 timer as well as problems with ...
2
votes
2answers
91 views
Will charging 2 capacitors seperatly still result in a lower value?
I have 2 150F 2.7V SuperCaps. I know if I put them in series, and charge them, I will get a result of only 75 farads. I am wondering if I charge them each separately to full capacity before putting ...
17
votes
4answers
1k views
Why is the unit for capacitance so large?
Most capacitors are in the µF, nF and pF range. I know there are some special ones that go that high, but at the time faraday was around, and the unit was named after him, they didn't have such a ...
0
votes
2answers
54 views
Changing the orientation of the capactior in a simple integrating op amp
How does the terminal relationship i=c(dv/dt) change if you switch the orientation of a capacitor from +/- to -/+.
Here is the "normal" model that I have been studying.
simulate this circuit ...
0
votes
1answer
74 views
what is Tau in this very simple circuit?
\$\tau = RC = 100 \cdot 22nF \$
or \$1000 \cdot 22nF\$? or should I add both the resistors together?
1
vote
1answer
70 views
16MHz Crystal with 2p load capacity: What load capacitors are necessary
I found a nice and cheap crystal on AliExpress which I want to use with my ATMEGA328 microcontroller.
Its load capacity is only 2pF. Normally I would say, that the 2 capacitors from the crystal to ...
1
vote
2answers
87 views
Flyback transformer - ambiguous schematics and other issues
I'm currently using schematic for a flyback transformer.
As you can see, there's a big problem - neither the schematic, nor the website describing it, give the value of the capacitor. It says ".01", ...
4
votes
1answer
65 views
Substition of electrolytic capacitors in surface mount applications
I understand there are advantages and disadvantages against using electrolytic capacitors over others, such as ceramic, but from what I understand the main reason of choosing electrolytic caps is ...
2
votes
1answer
38 views
Finding the total energy of the network in steady state
i got a network below in steady state im trying to find the energy in the network by the capacitors and inductors.
simulate this circuit – Schematic created using CircuitLab
My attempt ...
0
votes
0answers
56 views
Do film capacitors need to be isolated and current limited during the burn-in process to prevent them from discharging into one another?
Do film capacitors such as polypropylene and polyester film capacitors need to be current limited with resistors to each unit and isolated during the burn in process to prevent discharges into other ...
1
vote
1answer
73 views
Is there such a thing as a resistive bus bar to substitute many resistors?
I find myself in the position to design Burn-In racks for a capacitor manufacturing company. I am trying to replace the multitude of resistors on boards that limit the current and isolate each ...
3
votes
1answer
73 views
Is this a polarised capacitor
So I went to a local electronics retailer, Communica in Cape Town yesterday. I had a small shopping list including:
10x 10µF Ceramic Capacitor
10x 0.1µF Ceramic Capacitor
The vendor didn't have ...
0
votes
1answer
53 views
How do I read the markings on a Mitsuba capacitor?
I'm trying to identify a suitable replacement capacitor for use in a relay. The relay is by Mitsuba and uses a Mitsuba capacitor, which appears to print different notation on it than I have found in ...
0
votes
2answers
136 views
Is it possible to provide power using (effectively) a single wire?
I come to this question after a few thoughts on capacitors.
A capacitor essentially transfers (and stores) energy using an electric field through an insulator. The plates of a capacitor are not ...
0
votes
1answer
74 views
why and how do I use a capacitor in a switch circuit？
I have seen many designs of switch circuit:
I know that a capacitor will help anti-shake but I realy do not know how i can anti-shake. Does it work like a decoupling capacitor or a low-pass RC ...
0
votes
1answer
77 views
Trouble Detecting pF capacitance with Arduino
Im working with an EAP (electroactive polymer) thats capacitance changes when deformed. It varies between the ranges of around 0.5 - 3 nF. Im trying to connect it to an arduino to take readings that I ...
0
votes
2answers
86 views
Why do different resistor values dissipate power at different rates in RL and RC circuits?
Physically what is happening here?
RL
My thoughts on this are that the inductor supplies a certain current, and current through a larger resistor dissipates more power.
RC
This one I'm not so sure ...
2
votes
2answers
63 views
Mini Skee Ball - Detecting a ping pong ball
Background
I really want to do something with my raspberry pi, so I thought of a game that's a mix between skee ball and beer pong. Basically, the build is a mini skee ball board (about 20x24 ...
2
votes
2answers
60 views
LDO regulator (LD39300) output capacitor ESR not so small
I want to use the LDO regulator LD39300 of ST. To buffer VOUT, I thought about buffering the output in addition with a Aluminum capacitor of 6800uF in parallel to the recommended 4.7uF.
But in the ...
5
votes
2answers
102 views
Using a 5v voltage regulator - Capacitors necessary? Better options?
I am very new to electronics. I am learning as I go, and I haven't quite found the answers I need; when it comes to programming, I'm not afraid of mistakes as they happen constantly. With electronics, ...
4
votes
1answer
85 views
The voltage of capacitor across battery never reaches battery voltage
I made some homemade vinegar batteries. The voltage of each cell was measured around 0.45V. I have 18 of them in series and I measured around 6.5V for the whole chain.
Since the vinegar batteries ...
1
vote
2answers
67 views
Circuit with a MCP9700 temp sensor - What this capacitor is used for?
I have built a circuit that uses a MCP9700 to read the temperature as explained here.
This is the circuit schema:
I understand that C2 is used as a decoupling capacitor to clean up the noise ...
-4
votes
0answers
43 views
Capacitor discharge [closed]
I have a 1 microFarad capacitor and the range of the capacitor is 400 V. If I apply 315 V to the capacitor how many Volts will the capacitor discharge ? How to calculate the discharge of the ...
-3
votes
1answer
71 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
111 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
121 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
255 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
425 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
101 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
257 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
128 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
112 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
66 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
138 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
115 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
88 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
77 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
185 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
93 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
127 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?
18
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
51 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
174 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
239 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
345 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 ...
4
votes
2answers
121 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
63 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 ...
