New answers tagged power
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Troubleshooting for Power Delivery with Shunt Capacitor
It is not omega =5 kHz but f=5 kHz.
And yes, output is greater than input at this frequency.
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Best way to go from 5V to .95V to power an FPGA at max 15A
I think you could coerce the PE99155 into making 0.95V by inserting a voltage divider between EAINP and VREF. Check with the Teledyne apps folks. (You did, they vetoed it.)
It's also possible to ...
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Relationship Between Current and Power in a Refrigerator
"Defrost Amps: 4.4" means that up to 4.4A are used by the defrost heater, which is a separate thing from the compressor.
7.7A - 4.4A = 3.3A.
3.3A * 115V = 379W, which is quite a nice match ...
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Confused about the safe operating area of a MOSFET graph
Please note the test conditions in the upper right corner.
As long as you have a cooling mechanism that manages to keep the case temperature at 25 °C, the die will not go above 175 °C, and it will ...
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Microwave output power seems inconsistent with supply voltage
There is an impedance-matching network, presumably from a lower impedance at the die itself (which indeed cannot pull drain voltage below 0V), to the characteristic-impedance ports/pins/traces.
...
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Charge leakage in home appliances
I am unable to understand why do they get charged in the first place and why aren't they insulated instead of asking the user to work on grounding?
That link is specifically referring to a microwave, ...
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Need cheap variable positive/negative switching bench power supply with CC
To provide a formal answer, here is my take.
For hobby use where noise and minor inconsistencies don't matter, your design will do exactly what you need it to do.
I would suggest connecting a dual-...
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How can I calculate a relay's series resistor?
There definitely is a reason to limit the holding current of the relay, especially if you care about the power consumption. For that case one may use parallel RC circuit in series with the coil. The ...
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Would 5.5 x 2.1 mm female plug work inside a 5.5 x 2.5 mm male jack for DC power?
Not all plugs are created equal. Some plugs have full, uniform tubes that have little tolerance, and a nominal 2.5mm center pin will not fit inside one designed for a 2.1mm pin. They look like this:
(...
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Schottky diode fails probably due to temperature - LED driver
This is the schematic from the calculator tool, in which my design was based on.
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LC Parallel resonance induction heater
NO.
The law of energy conservation prohibits this.
In fact, when you put lossy core into inductor, your LC circuit becomes LCR circuit, when R is an induction loss, with different resonant curve and ...
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LC Parallel resonance induction heater
Quite the opposite, actually; a parallel resonant LC circuit has infinite impedance; the inductor and capacitor are simply exchanging energy. If you add resistance to change electrical power to ...
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Schottky diode fails probably due to temperature - LED driver
The long time to failure, among other factors, suggests a thermal failure.
The diode is very small (SMA package), and doesn't appear to have any special thermal consideration (large pours, vias, ...
- 27k
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Schottky diode fails probably due to temperature - LED driver
If the LED Vf is lower, the MOSFET duty cycle will be lower also, and the diode will conduct for longer during each cycle.
If current stays the same, diode dissipation is directly proportional to the ...
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Schottky diode fails probably due to temperature - LED driver
Make sure you simulate this circuit with parasitics or at least find the max current though the zener.
Odds are the diode died a thermal death, by looking at the picture. It also looks like there isn'...
- 78k
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How can I calculate a relay's series resistor?
Very good question... It takes me way back to my 70s school days when I was making all sorts of devices with relays. Then I reasoned like the OP does now:
The relay coil was wound with copper wire, ...
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Can I wire a 460V three phase heater (Modine model HE150) to my single phase 220V residential service?
The 460V model effectively has three heating elements, each connected between two phase conductors, delivering 50,000BTU/h when 460V is applied across them.
Using \$P=V^2/R\$ you can see that if you ...
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Potentiometer rated power and 16 LEDs
I have found the Joule Thief circuit to dim nicely and be quite flexible. I have worked up something that might serve as a starting point for doing what you want, and also learning more. Note that ...
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How can I calculate a relay's series resistor?
If you have a 5V relay, you give it 5V without series resistors.
I guess what you have been told applies to a case where you have e.g. 12V supply and relay with 5V coil, then you need to have ...
- 137k
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How can I calculate a relay's series resistor?
The value of 140 mW is not its rated power; it is just its nominal power dissipated at the nominal voltage. It is completely fine to operate the coil directly from 5 V DC, as long as 5 V DC is within ...
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How can I calculate a relay's series resistor?
I have been told that always that I add a relay to my design I have to include a series resistor (series with the coil) to limit current in it.
This is wrong advice.
The relay's datasheet will tell ...
- 171k
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Which is the more important switching parameter in MOSFET datasheet? Turn on/off/delay times or Input/Output/Reverse capacitances?
Which one should be considered for comparing the MOSFET switching
performance between 2 MOSFET part numbers?
Neither, if you are interested in a real circuit that switches a real load powered from a ...
- 443k
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Which is the more important switching parameter in MOSFET datasheet? Turn on/off/delay times or Input/Output/Reverse capacitances?
Timing tells you how long it will take for it to switch. So this sets the speed you can operate them, setting maximum frequencies which you can use.
Capacitance tells you how much energy you need to ...
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Problem with PoE implementation and newer switches
A class class 1-3 PD need to draw a minimum of 10mA in order to ensure that the PSE doesn't disconnect, according to the standard. In my experience Netgear PoE switches behave quite "loosely"...
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Electric potential - 2 power supplies
There is typically some non-infinite resistance between the probes of a multimeter or voltmeter. This can range from 100 k\$\Omega\$ for a cheap multimeter, to 10 M\$\Omega\$ for a professional model. ...
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Better off with a power fill and ground fill?
There are as many reasons to choose a layout, as there are layout strategies. And there are about as many of those are there are PCBs in existence. It's impossible to go into complete detail here, ...
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Better off with a power fill and ground fill?
It's very reasonable to do a ground fill on one side and power fill on the other.
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Power calculation for single phase heat treat oven
After brushing up on vector math to prove it to myself, the answer would seem to be P = 208V x 80A = 16,640W. Each of the 2 legs in use of the WYE secondary would have 120V x 80A = 9600W.
X component ...
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Absolute Maximum ratings of a device
For example, the maximum voltage applicable on a pin would be something like, 0V to Vcc+0.5V.
This is generally due to the presence of internal clamping and/or ESD diodes:
simulate this circuit &...
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Absolute Maximum ratings of a device
Bad idea.
The current flow into the pin will raise VCC above zero, turning the MCU on at some point. A series resistor changes only the time that this procress would take.
Crowbar type circuits are ...
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Absolute Maximum ratings of a device
Your assumptions are mostly correct. Many chips have ESD protection diodes from the pins to VCC, and it is the power dissipation of the current flowing through them that would damage them. The limit ...
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Current at 12 and 230 volts
The easiest way to approach this kind of issues I found is to always reduce to power instead of using current/voltage.
In this case the battery has ...
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Driving MOSFET with the PWM output of TL494
You can use discrete gate driver that consists from two transistors. I simulated it in LTSpice. The turn-of time (with given resistors) is roughly 300 nano Seconds. Turn-on time is roughly 100 nSec. ...
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Why use resistor in series with coincell for RTC backup power?
That is for safety approvals when using lithium coin cells.
Even if it wasn't for the regulations, this design uses a Schottky diode for low forward voltage drop, but Schottky diodes leak current ...
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Power calculation for single phase heat treat oven
When dealing with three-phase power calculations, you use the square root of \$3\$ (approximately \$1.73\$) as a conversion factor. The correct formula for calculating power in a three-phase system is:...
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TPS65251_Formula Error?
Looking in the TPS65251 datasheet Figure 21. Typical Application Circuit shows the same values of R10 and R11 from the 9.2.2.9 Output Voltage and Feedback Resistors Selection section:
From my ...
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TPS65251_Formula Error?
Equation 25 is wrong; the numerator and denominator are exchanged.
Section 8.3.6 of the same datasheet has the correct equation:
(There is a feedback link at the bottom of each page.)
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Most efficient way to generate 3-4 volts from less than 0.5 to 1.5 volts
You can do two things.
You can run the base of the joule thief transistor from a separate power source, like a fresh 1.5V battery, or a CR2032. Also, using a 10 ohm resistor plus a 1K (or 10K) ...
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Current at 12 and 230 volts
Case 1: Using a 12 V - 1 kW heater.
The heater draws 83.33 A from the battery.
Case 2: Using a 230 V - 1 kW heater and an inverter.
The heater draws 4.35 A from the inverter which, in turn, draws 83....
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shop equipment runs on 15v, want to DESIGN wiring so that a standard tool battery can run it
Battery powered devices usually have some tolerance to voltage input, so the voltage doesn't need to be exact. But, you should drop some voltage to get close to the target range.
Buy a battery adapter ...
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Current at 12 and 230 volts
The inverter passes power (voltage times current), not current, so a perfect inverter would still draw 83.3 amps from the battery.
Real inverters are not 100% efficient, so your inverter may draw ...
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Current at 12 and 230 volts
The current through the load isn't what matters here; it's the current through the battery that matters. Assuming an ideal converter, the current through the battery in both cases will be identical ...
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How to tell how much current can pass through a transformer
Here's a basic transformer specification (assuming there are no losses).
Primary voltage: 240 V 60 Hz
Secondary voltage: 24 V
Volt Amperes: 480 VA
Volt Amperes is the product of voltage and ...
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How to tell how much current can pass through a transformer
When you discover that you are looking at the wrong sort of transformer and, move-on to find the right sort for power AC applications, you would use the V.A rating of the device to calculate the ...
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How to tell how much current can pass through a transformer
Your first sentence has an error. A transformer does not change voltage down and necessarily boost up current.
And the currents you seek for the transformers are already in the first column.
And ...
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3 phase 4 wire inverter output common mode choke selection
I'm not sure, but won't this lead to saturation of the choke if the
phases of the 3-phase choke are not the same current?
It should be of significant concern but, whether a level of saturation is ...
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Can a switch take a higher voltage than it's rated for if the switching power is low?
At a practical level, if the current is definitely limited to 20mA then it should be fine. The insulation will hold (given the AC rating), and the current limit should prevent the issues with DC ...
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How to make a power switch using MOSFETs?
This is a fairly efficient way of pulling it off. Q1 can of course be tiny. Q2 needs gate and pull-up resistors in any case so sizing them to perform voltage division doesn't incur any penalty in ...
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Can a switch take a higher voltage than it's rated for if the switching power is low?
For this particular switch, it is more than capable to insulate 36 V. But, for a switch, it is much harder to quench DC once flowing than it is for the case of AC, hence the lower DC rating. But as ...
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IEEE 34-Bus Radial Distribution Test System
To answer your question directly, I believe that these are two completely different distribution system models, related only by the fact that they both happen to have 34 buses. The second is the one ...
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