New answers tagged current
3
votes
Transistor switching speed
I won't go further than a very simplified (1st order) model of what's going on to help develop a meaning for \$f_t\$. There are higher order models. But to a first order the following approximation ...
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0
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Transistor switching speed
Switching speed of transistor cannot be defined with exact number.
For high efficiency SMPS design you don’t want the transistor to be in linear region more than example 2% of overall time.
On other ...
- 1,965
0
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RMS current measurements using Arduino uno
It depends on how they arrive at the RMS result. Some devices may assume a sine wave and just multiply the peak voltage by \$\frac{1}{\sqrt2}\$ or 0.707. It might not be a literal multiplication as ...
- 25.1k
3
votes
Accepted
Can a voltage higher than LED maximum be used when using constant-current LED driver?
The sink driver requires 0.8V to get guaranteed output current, so for 2.9V maximum Vf LEDs you should have 3.7V supply voltage minimum.
It won't hurt the LEDs but you might not get full current or it ...
- 407k
0
votes
How to know what size diode to use for inductive spiking?
The diode needs to be able to handle the current that is flowing through the inductor when the transistor is conducting. This is because the current through an inductor can't change abruptly.
However ...
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2
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How to know what size diode to use for inductive spiking?
You really should look into Transorbs for this, acronym TSB. Although they have a power ratings, they are designed for short duration surge events. Incidentally they are available in both unipolar ...
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3
votes
Accepted
Is a capacitor a memoryless system?
then the current only depends on the derivative of voltage at that particular instant of time only,
You are just trying to shift the memory to the voltage input, rather than the capacitor state. The ...
- 169k
2
votes
Current varies with constant firing time in an SCR
There are many things that affect the charging current of a battery, and the applied voltage is only one of them. The resistance of the battery itself depends on things like its state of charge, its ...
- 175k
1
vote
Maximum LEDs on a pin of an AVR Microcontroller
You are correct in that the microcontroller's pin I/O current spec limits how many LEDs you can drive. In general, you should not exceed the datasheet limits given for I(oh) and I(ol) for a single pin,...
- 55k
0
votes
Why, when conductors are connected in series, their current strength is equal?
The current through the conductors is going to be determined by the total resistance, which you get by adding together the resistance of each conductor.
Moreover, what we see using Ohm's law, is that ...
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1
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Why, when conductors are connected in series, their current strength is equal?
Because the electrons have nowhere else to go.
If you think about electricity as the physical movement of electrons, then in a DC circuit all of the mobile electrons enter at one end of the two joined ...
- 21.4k
1
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Why, when conductors are connected in series, their current strength is equal?
Perhaps a water pipe analogy is in line.
If you have two pipes with different diameters connected in series, will the flow rate (liters/minute, gal/minute) be different in each section if there are no ...
- 10.3k
0
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Why, when conductors are connected in series, their current strength is equal?
1 amp is equal to 1 colomb's worth of electrons passing a given point in a second. 1 coulomb is about 6x10¹⁸ electrons.
If the two wires are in series, then the current in the two must be the same. ...
- 19.5k
1
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Why, when conductors are connected in series, their current strength is equal?
Not only conductors. This logic applies to anything: insulators, vacuum, plasma, whatever.
The reason lies in the conservation of charge, which is a principle deeply rooted in physics. The charges ...
- 22.5k
1
vote
Accepted
Distribute power from one battery to multiple devices
All these components on that system, works in certain amount (range) of voltage, right?
Right.
how can I create a system - above the main system - to distribute power correctly
Do not power the ...
- 22.8k
0
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Should I replace my stepper driver since my motor is acting up?
If it worked well for such a long time, and changing the driver to a new one doesn't help, then I doubt it's the problem. What comes to my mind is that the vibration from the motor caused a solder ...
- 11
2
votes
Why is a push-pull transistor configuration asymmetric?
Each transistor is responsible for passing current in two different parts of the input/output waveform, between which current in the load changes direction.
The upper transistor is allowing current to ...
- 39k
6
votes
Why is a push-pull transistor configuration asymmetric?
Everyone has already pointed out that one of your transistors is arranged incorrectly. So I won't belabor it here. Sufficient that you know it won't work.
The phrase ...
- 11.2k
-1
votes
Why is a push-pull transistor configuration asymmetric?
Your circuit is invalid. Try something like this. It can operate from a single-ended power supply. Reference the amp to 6-volts. Circuit reference https://circuitdigest.com/electronic-circuits/push-...
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8
votes
Why is a push-pull transistor configuration asymmetric?
But that's not a valid push-pull circuit to begin with.
You have the PNP transistor upside down.
Even if it were correct, for negative output you would need a negative supply and you don't have one.
...
- 159k
0
votes
Why do I measure different resistances in the same wire at different current levels?
My first comment would be regarding your poor measurement configuration that will surely not give very accurate results.
The voltage taps (I guess these are the crocodile clamps) position is not well ...
0
votes
Voltage and current on two identical TVS diodes in parallel during a voltage spike
With 2 identical TVS diodes, surge current will be shared equally and, the clamping voltage will be dictated by the current flowing through either of the 2 devices (it will be somewhat less than the ...
- 465k
1
vote
Accepted
How to measure battery voltage during charging?
Will I read battery voltage/charger voltage/intermediate voltage between 15V and 12V.
No. If the meter probes are placed across the battery, you will measure the sum of the battery voltage and the ...
- 17k
1
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How to measure battery voltage during charging?
If your battery is 12V and charger is 15V then connecting the charger to the battery should show 12V or something very close to 12V as the battery voltage cannot jump instantaneously as it needs ...
- 159k
1
vote
How to measure battery voltage during charging?
the battery voltage or the charger voltage or some intermediate voltage.
Yes, yes, and kind of yes.
By definition, the battery voltage and the charger voltage are exactly one and the same because ...
- 22.8k
1
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How much current will a BJT transistor draw through its base?
There are two primary viewpoints for the BJT: the DC operating point and the AC behavior around that DC operating point. You must keep these ideas totally separate in your mind. The connection between ...
- 11.2k
2
votes
Accepted
How much current will a BJT transistor draw through its base?
Shouldn't \$i_B\$ be the full current we'd get between base and emitter if we simply had a diode? If it's not, then how do we predict what \$i_B\$ is?
It is.
But you need to remember that \$V_{BE}\$ ...
- 175k
0
votes
How much current will a BJT transistor draw through its base?
The transistor will draw more current from the base if you disconnect its collector.
Yes, the BE junction behaves like a diode but here its cathode follows the anode, so the current is too small.
You ...
- 17.5k
1
vote
Accepted
Negative current flow contradiction?
You made two errors:
your KCL equation did not conform with arrow direction.
The sign of one or more of the amounts did not conform with arrow direction, leading to a situation which is physically ...
- 39k
2
votes
Powering on a laser diode that exceeds PSU max current
To make a quick test of that power laser diode, put a small resistor in series, and a moderate size capacitor across the output of the power supply.
In the diagram above, a 1µF cap charged to 10 or ...
- 4,667
4
votes
Powering on a laser diode that exceeds PSU max current
Edit: See also comment by DrMoishe Pippik
If pulsed operation is fine (as it is here), you can get away with a capacitor, inductor, Power MOSFET and a signal generator. The idea is to convert the 10A ...
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2
votes
Why is the power conserved in a phone charger?
I don't understand because in a generator or a battery, when the voltage increases, the current also increases according of the resistance in the circuit because U=RI.
Why does the current increase in ...
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1
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Why is the power conserved in a phone charger?
Why is power conserved? Why does the increase of voltage not increase
current?
Because we choose components, topologies and, designs that attempt to conserve power as much as we can. It's a vital aim ...
- 465k
0
votes
Why is the power conserved in a phone charger?
why is power conserved?
The Nature just works that way. That means: our Universe happens to have this power conservation property. It follows from more basic laws, but that's how it is. Power cannot ...
0
votes
Why is the power conserved in a phone charger?
You are right, U=R*I is always true for a pure resistive circuit (where only DC is involved!)
When a transformer (or switching regulator) is present, you have 2 circuits, one on the primary side and ...
- 7,653
0
votes
Do we need MPPT in grid synchronization and string inverters?
As stated by Dave Tweed we use an MPPT only when we have a large sink that can consume a huge amount of current. At times of synchronizing and load providing in string inverter the load is limited and ...
- 669
1
vote
I have so many questions about this method of grounding in this video?
I didn't watch the video (don't have time) but I have measured large voltages on the external conductive surfaces of various electrical equipment many times. It does not necessarily mean the voltage ...
- 5,327
15
votes
Why does a battery have a limit for current in amperes?
The electrochemical reactions in the battery can only take place so fast. With some batteries the current should be artificially limited to protect the battery from self-destruction. It may be able to ...
- 407k
12
votes
Why does a battery have a limit for current in amperes?
An ideal voltage source can supply whatever current the load wants, unlimited.
But a battery is not an ideal voltage source. So, it can't.
A battery can be modeled as a voltage source plus a series ...
- 22.8k
0
votes
Trying to T-tap wires of different gauges. Do these t-connectors even exist?
A busbar should be a better choice than taps.
Something like this will get you 20 connecting points and is rated at 50 A. If you put two LED modules on each screw you could use two busbars per side, ...
- 25.1k
0
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Trying to T-tap wires of different gauges. Do these t-connectors even exist?
Assuming your proposed solution it to use IDC taps (where the main wire is not cut at each tap only its insulation is pierced) then yes that could work.
There's a fairly large wire gauge difference, ...
- 34.6k
1
vote
Accepted
Trying to T-tap wires of different gauges. Do these t-connectors even exist?
There are not a whole lot of elegant ways to split out that many taps from a single feed, but I've had success with buying plain copper bar stock (or silver plated if the budget allows) and drilling/...
- 20.3k
1
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Why does a 230V 16A socket supply only the needed current to loads?
If I connect a 150W laptop charger to a socket that supplies at home 16A 230V, it will only draw the necessary amperage needed for the laptop charger at 230V. Why?
The definition of electrical power ...
- 5,327
0
votes
Why does a 230V 16A socket supply only the needed current to loads?
Your socket rated at 16A does not know how many hundred or thousand amps are available from your electricity provider and it also does not know how much your laptop needs for charging. If you connect ...
- 159k
0
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Why are the 10A inputs on many multimeters unfused?
I'll provide a reason why it may not be such a bad thing after all to have an unfused input.
I have blown a multimeter fuse on the 10A input several times. At first, I didn't understand what happened ...
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