New answers tagged power
1
Here is a schematic from others that use TDEM's to do research, which is an H-bridge with TVS diodes to short out the high voltages that may come across the inductor when it is disconnected:
Source: https://www.researchgate.net/post/How_to_evaluate_the_performance_of_a_time_domain_electromagnetic_TDEM_or_TEM_system
This would be a starting point for a ...
0
As far as I know, you don't need a power distribution block in systems which has more than one 3-phase motor. A power distribution block helps you to create more efficient wiring.
When you use a distribution block, it is no longer necessary to switch every device in the control circuit back to the power source. This can be done with the help of one large ...
0
As you calculated correctly, the 1.5kohm resistor will dissipate 0.384W if there is 24V across it. So, about 10% of its rated power.
Will it be damaged?
Not at room temperature, however, at higher ambient temperature you should check the power deration curves.
E.g. the SMW520RJT made be TE connectivity, a 20 ohm, 5W resistor, has the following ...
1
You could probably do this, the problem is if you did, a way would be needed to make sure you don't send more than 2A through one TPS2215A. The other problem is matching between devices, if one device has say 10% more resistance, then the other device would conduct more current and dissipate more heat.
But TI also has a TPS2120 that is rated for 3A which ...
6
I want to point out one thing that the other answers are ignoring, or at least glossing over.
In this measurement, we stop the flow of current in our inductor, and this causes current to flow in the earth below it. That means we're effectively using the earth itself as the secondary coil of a flyback transformer.
In a flyback transformer, the primary ...
0
There are different kinds of generators. Some do supply constant electricity with monthly schedules like nuclear and thermal power plant, these can't dynamically change the production.
The variable part of the demand is supplied by power plants that can quickly turn on and off, these are gas turbine, hydroelectric plant, diesel. In case of increased demand,...
0
Just trace the signal from port 1 to the other ports, regarding it as a wave with delays causing the given phase shifts. The zeros of transmission are caused by the two paths from the input to the output arriving at the output just out of phase, so they cancel each other out. It is easy to see by adding up the phase shifts that s12 and s14 must be the ...
4
Can you collapse an inductors magnetic field instantaneously?
NO ….you can neither create nor collapse a magnetic field instantaneously since there is always some L and R time constant involved.
You CANNOT reverse the voltage on an inductor either (at least not in any practical circuit) and get lower discharge times.
Perhaps a simple example may help:
...
0
They ain't collapsing no field instantaneously. At best it's limited by the speed of light; in reality they're generating some high voltage discharge, or the energy of the field is being dissipated into the soil.
In open air, you'd discharge the coil into a spark gap. "Instantaneous" is literally wrong, but figuratively, if you get the coil strength down ...
-1
The problem
PV has enough power to charge a smartphone, but every day when power reduces two (2) phones failed ( in succession?) with damage due to PV charger.
Why
When PV source dims and voltage drops, smart phone's charger cuts out. THen PV voltage rises to an adequate threshold and a smartphone charger turns on again with a surge demand power and PV ...
0
Who would cover the electricity difference if the generator does not
end up producing the quantity stated in the trade or where would the
overproduced electricity go, if the consumer has estimated his
consumption poorly?
This is why continuous grid management is needed.
Electricity in the grid in most cases cannot be stored for later use. It is a ...
0
The simple answer to "where would the overproduced electricity go" is that the generator will not produce excess electricity and that causes a reduction in the fuel that feeds the driver of the generator. It is more complex than that. Some types and sizes of generating equipment are easier to "throttle back" than others. Suppliers or groups of suppliers have ...
1
where would the overproduced electricity go, if the consumer has
estimated his consumption poorly?
It doesn't go anywhere - if the consumer under-consumes compared to the original prediction then, that under-consumption is physically less-current being taken and less-power being supplied by the generator.
Electricity isn't like a delivery van setting ...
5
The problem is quite likely related to your breadboard. They are not very good for high currents.
Why? Well there are a few reasons, but it all comes down to your components not being that well connected.
Firstly you inevitably have a bunch of thin wires going between everything. I highly doubt your average jumper wire is rated for 2A. But even if it is, ...
0
I would recommend you research UVLO a bit more (Under Voltage Lock Out). As that is the thing you're describing. Are you sure your current chips don't already have some feature like this built in?
If not, it's fairly easily done with a comparator and a couple of resistors.
But there are a couple of challenges. Firstly when you power on, there could be a ...
1
The device you're looking for is called a "voltage supervisor" or sometimes "reset controller". It monitors the supply voltage and asserts the reset input on the microcontroller until the voltage is within a particular acceptable range. Some also add a short delay after the voltage becomes acceptable before they release the reset signal
Many ...
1
One reason you may not have seen circuits like this is that most designers would use a dc-dc converter rather than a linear regulator, in order to get the most energy from the battery.
In any event, I do see some problems. First, there is no mechanism for the microcontroller to pull the EN pin low and shut down the LDO. The way you have arranged the diodes ...
0
If you reduce the voltage supplied to a fixed load resistance then the load current must decrease according to Ohm's Law. But if you use a buck converter to decrease voltage the supply current will reduce more than the load current.
For example, if you power a 5Ω load from a 10V supply then the current will be 10V/5Ω = 2A. If you then drop the load ...
1
The available power is based on Pin = Pout,
BUT, if you reduce the voltage into a fixed value resistor, then the current reduces appropriately as per Ohm's law.
Your confusion is about the power staying constant, it is available if you change the resistor...
1
Stumbled on this question while looking for an answer regarding a charger I bought that actually fits your needs very well.
Wurth Electronics Wireless Power 200W Development Kit
You can actually download the BOM, schematics, and firmware here, if you really want to build your own or need to make changes to the design.
Mouser Article
Mouser Purchase Page ($...
1
You can detect that the power has failed because the microcontroller is starting up.
If the power just came on, then it must have been off before. Therefore, there was a power failure.
Perhaps I haven't understood the question correctly.
0
A flip flop will lose it's state if not powered. A better method would be to have a routine to write a counted value to a ROM. If the counter started from zero then you would know about an upset.
Another way to do this would be to use an RTC IC and a microcontroller
You could also have a brown out detection circuit and a enough power to run the micro for ...
2
this link shows a precision current reference circuit with approximately a 10ppm stability http://www.ti.com/lit/an/sbva001/sbva001.pdf
0
There are 2 requirements from what I can see:
The generic I/O power (see section 2.5 in the datasheet) should all ramp up together and can precede \$V_{DDR}\$ although \$V_{DDR}\$ can ramp up with the generic I/O power; the LV supply should follow this.
In section 3.4.1 (Recommended operating conditions for 3.3V operation) there is a caution:
VDDE_C and ...
-1
I returned this power supply and purchased another 10A12V power supply. It is able to supply 10A as expected.
9
Assuming you're asking about the die, then parts with the same part number from the same manufacturer will typically have identical dice inside regardless of what package they use. There's no rule that says they have to, though; they could use specially-designed dice to fit more conveniently in different leadframes if they had reason to.
Economically it ...
1
There are four options:
A three-phase VT wound on a three-limb core.
A three-phase VT wound on a five-limb core.
Three separate single-phase VT's.
A voltage measuring device that measures your 600VAC directly without a VT. (Where I come from, direct voltage meaurement, without a VT, is used up to at least 440 VAC.)
Of these, I would recommend that you ...
1
For a modern A/V receiver 'speaker out' to line level (say you're using Zone 2 out the back of your A/V receiver and wish to feed another amp that handles only outdoor speakers but you wish the outdoor amp volume to be controlled by A/V receiver) then:
R1 = 3.9K @ 1watt
R2 = 430ohm @ 1/2watt
and
R1 connects from Speaker out RIGHT+ to RIGHT/RCA+
R2 ...
1
A computer 12V fan can be powered by 5V just fine. It will still work at a low speed but sufficient to actually cool and it will be significantly more silent. I use this very often and it suffices for many applications.
Going from 24V to 18V is like going from 12 to 9, so it will definitely work at a sufficient speed to be good in most scenarios.
If you do ...
-1
The cooling fan will run slower, which may or may not cause something overheat.
0
In the context of the power grid, AC power is generated and transmitted through transformers in three phases 120 degrees apart. The third harmonic (triple the frequency) is identical for all three phases, which you can verify by plotting the sine waves. When you connect a load between any two phases, the third harmonic voltage is the same on both wires, so ...
6
Some of the maintenance tasks we do on transmission lines (Rural Australia; 11 kV - 132 kV)
Grade the access roads along the line corridor - access roads tend to get overgrown / washed out over time. Inacessible roads are very inconvenient when "running the line" to find a fault at night-time.
Cut down trees encroaching on the line.
Perform visual ...
0
Mechanical efficiency is the real output power over the developed output power. Thus, mechanical losses are basically friction losses. Keeping this in mind, you have to calculate the power flow in the rotor. Once you have the power in the rotor you should subtract the power lost due to resistance of the motor's winding. Your mechanical efficiency is then ...
0
Is it possible to get 20 volt, 2A from 2 power bank by connecting 4 x USB ports, each rated at 5V, 2A
Is it possible to connect 4 x USB 5v, 2A to get 20V at 2A
or 4 x (USB 5V at 2A) to get 1A current (parallel circuit and buck)
You can
Use completely separate power banks connected in series in series to get higher voltages.
eg 4 x (USB 5V, 2A) ...
0
Decades ago I trained a team of people to perform RFIC design. But almost ALL the circuits were broadband, covering 1 or 2 octaves of input range or output range, in the 100MHz to 1,000MHz range. (OK twas one LO buffer with 2+ GHz requirement, and prescalers with similar requirement).
We faced this question: to match, or not to match. I explained we could ...
1
For example, if one has a sensor which can be modeled as voltage
source call it Vs. Imagine it is outputting mV level voltage signals
and it has 1k output resistance. And if we want to amplify it we would
use an amplifier with a very big input impedance like 10Meg so that
most of the Vs reach the amplifier input.
You might do that if you are only ...
0
Automotove alternators almost all have a regulator that varies the current through the wound field coil in the rotor, producing enough excitation in the stator to generate the required voltage for the system. Once the battery is fully charged, the field current drops to the point that the alternator is only producing enough output to address the remaining ...
1
Multimeters measure resistance by applying a known voltage across and measuring the current, or vice versa, a known current being applied and measuring the voltage. You can't measure devices that are on this way because the voltage of the device is almost always higher than the voltage being applied, overriding it.
On top of that semiconductors can have ...
2
You can't measure resistance between VCC and GND when power supply drives voltage between VCC and GND. The multimeter is confused because there is an external voltage source. Also, measuring resistance of anything that is not a resistor will give weird readings, as they can have nonlinear behaviour like LEDs or semiconductors. At most you can measure if ...
1
What could be causing this?
When the board is off this is a little unusual because most often the leakage current through transistors or loads when the power is off is in the 1-100kΩ range for most of the boards I have with voltage regulators on them. If you had something with a high side switch or a relay this could explain why the numbers are so high.
...
1
If you search the Web for this issue you will find LOTS of people that have tried everything to get rid of the "under voltage" indicator. The problem seems to often be the power supply or the cable being used.
In your case it sounds like you have tried everything!
This is not a fix of your problem, but it is a way to get rid of the under voltage warning.
...
0
The Ohm’s law states that the current through a conductor between two points is directly proportional to the voltage across THE (same) two points. It’s applicable to all circuits and transformer is not an exception. A mistake that led to contradiction is that (decreasing) current is measured not between the same points, where (increasing) voltage is. Current ...
0
If using two different DC brush motors, one to drive the other. The output V*I=P, power out is still less than the input ( due to losses). But it works as a DC transformer with the sum of both motor impedances in series.
Most motors are rated in V/kRPM, Volts per 1000 RPM for no load, thus the sum of series impedance affects the output voltage by the load ...
3
Absolutely! That is the basis for motor-generators, which, before power semiconductors, were one of the few devices able to change DC voltage with comparatively little loss.
Of course, stepping up voltage comes with a concomitant reduction of current, so you don't gain any power. E.G. 12 volts at 30 amps is equivalent to 120 volts at 3 amps, 360 watts.
...
0
You will run into some mechanical problems with your arrangement mostly.
However, if you had a DC machine with a field winding instead of permanent magnet excitation, you can control the field strength.
The stronger the field, the lower the speed for a given voltage
The stronger the field, the higher the voltage for a given speed
1
You can easily get more output voltage from one motor driving a generator, the same as using an electronic voltage boosting circuit or using a transformer for AC. But the power cannot increase then the output current will be a little less than the input current.
Are you thinking of Over Unity to feed the higher output voltage to power the original motor ...
3
You would probably be best served with an 10V LDO for the gate drive (or fixed 12V if you like) with 2k2 pull-up resistor and using cheap BC847 NPN transistors to pull down the FET gates.
5kHz PWM is not nothing, i.e. 200µs total cycle time. To give yourself a reasonable duty cycle range, you should aim for 10µs rise time or less, which works out to 95% ...
1
Considering switch-mode regulator ICs are cheap and can be made to work with few external components, why not simply have two? One directly for the microcontroller (unless you do sensitive analog measurements, that will not suffer under being directly driven from a SMPS), and one for the gate driver.
You could sensibly drive both directly from the 24 V; ...
0
Get a 12V DC DC converter with isolation. Make sure the input voltage can handle 12V and the output voltage is a 12V output.
There are some that can be found at digikey
With some searching some can be found with terminals.
Before you try that, try a clamp-on ferrite on the wires to see if you can increase the inductance and stop high frequency noise.
0
You are confusing the "Lossless Transformer's" function with the resistor's function. The resistor's function is to convert the applied voltage and current flow to thermal energy for dissipation. The transformer's function is to convert an applied input voltage and current to another voltage and current with NO DISSIPATIVE LOSSES. For 10 Watts input at the ...
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