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Questions tagged [power-dissipation]

Anything related to power dissipation in electrical and electronic circuits and components, i.e. the process in which electrical energy is converted to heat when current flows through them.

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Conceptual paradox with resistance in loop/node analysis

There are loop/mesh analysis and node analysis corresponding to Kirchhoff’s voltage law (KVL) and Kirchhoff’s current law (KCL), respectively. Let's consider three elements, R,L,C, connected ...
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2answers
95 views

Electrical Heater Confusion

I know that a semiconductor material, that is usually used for heaters in variety of application, heat up due to high current, which flows through them or high power dissipation across them. But lets ...
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1answer
25 views

GaAs and GaN as low temperature carriers in transistor

I've been looking at HEMT to use at low temperatures. GaAs and GaN seem to be discussed often in the context of low temperature amplification. My questions are twofold. To be suitable for low ...
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1answer
94 views

Precaution and Rules to Paralleling Power MOSFETs

I'm going to use a Full Bridge Inverter for my application. The problem is that the current which flows through the MOSFETs when they are ON can reach 70A RMS and the power dissipation is too high. ...
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1answer
47 views

how to adjust drain bias to keep power dissipation constant (HEMT)

I am reading a chapter in a thesis about using HEMT (high electron mobility transistor) as a cryogenic amplifier. The measurement scheme is to use the gate voltage fluctuation's influence on the drain ...
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3answers
270 views

Heat dissipation through ground plane and other thermal considerations for 3W LED

In designing my first PCB ever to mount a 3W white led (shown above) thermal dissipation is a concern. It is a simple PCB and I don't have the ability to add any heat sink beyond the ground plane of ...
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1answer
99 views

Testing regulated power supply: 100 mA current sink

Disclaimer: I'm trying to learn about circuits on my own. I'm reading as much as possible to avoid any basic mistakes, but if there's any, please point it out and I'll investigate further in that ...
2
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1answer
84 views

Is this the correct way to calculate IGBT power loss?

I am having trouble obtaining the power dissipation of IGBTs. It does not have a buit in diode and it isn't driving an inductive load. So I read in an application note that IGBT power losses are ...
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2answers
41 views

Does LTSPICE automatically include avalanche parameters in its power dissipation measurements?

Does LTSPICE power calculation window like this take into consideration MOSFET avalanche parameters and include them into the overall average power value? That particular image is for a resistor ...
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3answers
40 views

Thermal resistance - Temperature transistor

I have a transistor with Vsupply = 24VDC, VCEO = 45VDC, ICE = 20mA. How to calculate the delta T (rise in temperature) of this transistor. I would like to know what thermal resistance I may have at ...
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1answer
67 views

Efficient electronics components [closed]

Imagine budget is not an issue and you are asked to design the most efficient circuit. With efficient, I mean that the power used to perform the functions is used solely for that and is not dissipated ...
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1answer
41 views

Why the rotor core losses are very tiny compared to the stator core losses in an induction motor?

Book says rotor mostly runs at speed near to synchronous due to which the relative velocity between rotor and stator magnetic field is very less. Correspondingly making rotor core losses tiny and ...
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1answer
60 views

sizing voltage regulator [closed]

I am to size a 3v3 voltage regulator, It gets at its input 12VDC maximum. And the load can consume up to 150 mA (few leds, 20 NMOS control, ADC control, microntroler supply...) and ambient ...
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1answer
123 views

Calculate temperature rise on an inductor in a switching-mode power supply

I'm a little bit confused about this matter. I've got a switching-mode battery charger (basically, a power supply) based on the LT3650. I want to know how much the inductor temperature is going to ...
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0answers
71 views

Using 40w tubelight choke to light a 39 w tube

Can I use a 40w tubelight choke to power a 39w 3feet T5 tubelight? Will the excess wattage create any problem such as decreasing the life span or causing the tubelight to burn out?
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1answer
27 views

Built in Tablet Chargers in the Van--Voltage regulation heat dissipation a problem?

Ok, for fun and enjoyment I have decided to build in chargers in a number of positions on the "Mom Van." But either I can't do math, or I am missing something. I want tablet style chargers capable ...
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5answers
428 views

How closely should I space my thermal vias?

How closely do you pack your thermal vias? I know that more vias divides the amount of heat each via can move and that smaller vias allows more vias to be packed together. Knowing this, it seems ...
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3answers
132 views

how to calculate the total power dissipation of below circuit

how to calculate the total power dissipation of below circuit
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1answer
237 views

Calculate the total max power dissipation in CLASS AB push pull for reactive loads

As worst case we can assume in reactive load the same power dissipation with the resistive part of that load. Thus for a 8 ohm impedance with phase angle of 60°, we can use \$R_L=0.5*R_{Reactive}=4\...
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2answers
157 views

Class A power amplifier: power dissipation

Let's consider the following class A power amplifier: And here is the time-domain simulation of the power dissipated across the transistor: As we can see, the power varies from approx \$0.1W\$ to \$...
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3answers
441 views

Is “switching frequency” measured for a full cycle or half cycles

Here's a sample datasheet from a FET driver: http://www.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=ucc27211a&fileType=pdf Section 9.2.2.5 describes calculating power dissipation....
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2answers
280 views

Heating element 1500 Watts 230V, can we reduce the size by cutting it? [closed]

I have a heating element commonly used for electric stove ,its 1500 watts 230V what i need is reduce the size to maximum because i cant fix it in my project which don't have enough space to fix the ...
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2answers
386 views

BJT Constant current LED driver

I need to build a constant current driver for a LED with a forward voltage of 3.4V and 350mA maximum current. The driver will be controlled by a PWM signal from a 3.3V MCU. Reading this post and ...
2
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3answers
276 views

Peak power pulse in parallel MOSFETs

I have a circuit like the one shown below. To make the schematic easier to read, I only show 2 FETs in parallel. I actually have 8 identical FETs in parallel. The HT0440 is a high-side N-channel FET ...
18
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1answer
1k views

TO-92 not getting hot enough

I am controlling a DC fan by an AVR MCU and I am curious about the thermal characteristics of a 2N3904 NPN transistor over which the fan is connected. Reading the transistor's datasheet, I find the ...
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1answer
130 views

Heating air through resistor heat dissipation

I am working on a project and have been delving into electronics. I am still quite new, however, so I would love to hear any info/advice you have! I would like to heat incoming air through a short ...
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2answers
1k views

Understanding power dissipation of a diode in a datasheet chart

According to this chart of a diode's power dissipation over temperature, the power dissipation would decrease as temperature goes up. But wouldn't it be the exact opposite and even more power be ...
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1answer
33 views

Current distribution plot analysis?

I was modeling current distribution in a component: And I plotted the \$ \vec{J} \$ to simulate & understand the current distribution throughout the conductor, all the flows make sense, except at ...
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2answers
73 views

What is the reason CMOS took over as an inverter for fabrication of gates?

I get to know that the static power dissipation is zero in case of CMOS where as there is some static power dissipation in NMOS with saturated load and linear load and with NMOS with depleted load. ...
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5answers
340 views

How to decide dimensions of PCB heatsink?

I am using MCP73213 IC for charging my 2S Li Ion battery. I want to use this IC for 1 ampere charging during constant current charge cycle. My specifications are as follows. Input source voltage : ...
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3answers
798 views

How to limit current for voltage regulator/decrease power dissipation?

I need to power a 5V device that needs more or less 1.2A in order to work correctly. I'm using a 13.8V power source with two diodes in series (1N4007) to limit the voltage to roughly 12V. I tried ...
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2answers
104 views

How to measure power dissipation through each component in PCB board?

I have designed an RF based PCB board and for testing purpose I would like to measure the power dissipation through each component. Someone suggested, by measuring the temperature of each component ...
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2answers
1k views

How does static dissipative foam work?

I am planning to build a grip-release sensor using the foam. I'm pretty interested in the way it works. Does the resistance in circuit increase or decrease when force is applied onto it? And this will ...
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2answers
66 views

Finding the heat dissipation but calculations not going right?

I am trying to find the heat dissipation from a 20000 V 1 A filament which is on for 1 second. I just randomly came up with this to try to test my understanding of joules first law and ohms law with ...
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2answers
347 views

SMD resistor with same resistance but with different power will reduce the temperature of my PCB?

I need to reduce the amount of heat generate by some resistors on my PCB. My question is if I use a 10ohms - 2 watts - 2512 SMD resistor instead of a 10ohms - 1 watt - 2512 SMD resistor, the amount ...
2
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3answers
106 views

Power supply design for CPU: Define maximum current needed

This is something that is troubling me in many of my projects and I would like to know if there is any standard approach to it. The question is how should I correctly design / dimension my power ...
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1answer
434 views

peltiers in series

Im trying to understand the way a peltier modules behave as they are new and intriuing to me, I have ordered a few tec1-12705 units from china and done a little research trying to understand it. Some ...
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3answers
56 views

Are parts parameter supposed to agree with each other in datasheets

Say, given a power BJT that has a \$V_{CE_{SAT}}\$ = 2V and rated at \$I_{C_{MAX}}\$ = 6A, but \$P_{MAX}\$ = 8W. Clearly, even only considering the \$P_{C}\$, it cannot continuously provide that ...
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0answers
59 views

How much energy is lost between (solar panels+battery pack) & DC operated electronics due to conversion

For the sake of simplicty; I have solar panels generating Xvolt, Yamperage. All of the power will be used by Xvolt devices. But all of the house and device adapters are designed to use AC grid. So ...
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2answers
141 views

Heat dissipation in a DIP Solid State Relay

I am working on an application that switches a high power (15 W typical, 100 W maximum) resistive load at 230 VAC (RMS) from a 5 VDC control line. For this I plan to use a Solid State Relay. I am ...
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2answers
203 views

what is the wattage rating of a 2 watt resistor in oil? [closed]

I have a termination resistor for a antenna and while it is rated at 300 watts, I opened it up and it is not capable of dissipating 300 watts as constructed. It is in a PVC tube and has sufficient ...
2
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1answer
109 views

AC circuit calculations

I'm a new student to electrical and electronics engineering. I've been given the following calculations regarding an A.C. circuit with resistors and a capacitor in series, and I'm not sure if I've ...
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1answer
354 views

does heat kill hard drives? hhd lifespan due to heat [closed]

These days it's hard to buy an external 3.5" hard drive with a fan inside or well heat dissipation design. I have 4 of such hard drives, and two have already failed in first few months. Here is the ...
3
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1answer
106 views

N Mosfet with 8 pinout

I was wondering why some MOSFET transistors like This one has 8 pinout instead of 3 ?
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2answers
291 views

Precautions needed to parallel P-MOSFETs as high side load switches?

I plan to use P-MOSFETs (SI7463) as high side load switches, with a slight soft-start (to be tested and tweaked after PCBs are made). I'd like to parallel them in order to make the equivalent Rds-on ...
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2answers
83 views

Heat vs derating power resistor Lithium battery discharge load tester

I am making a Lithium battery discharger/tester to test some 18650 batteries that I found in some old laptop cells because I am too poor to buy some brand new battery which cost more than 5 USD each. ...
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2answers
2k views

Average power dissipation in radar

Hello there here i want to calculate average power dissipation of radar My question is here i tried to solve it this way Average power = peak power*Duty cycle here transmitted power is 300kW and ...
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5answers
1k views

Power dissipation in resistor from triangle wave

How to calculate power dissipation through resistor from specific wave form? Wave: Triangle, 1V, 1kHz Resistor: 10kohm Q: What is the power dissipation in the resistor, considering frequencies up ...
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4answers
2k views

What is making my DC/DC converter's capacitor to blow up?

I'm having some capacitors blown up and I am not sure what's the cause of this. It is definitely NOT OVERVOLTAGE and NOT in WRONG POLARIZATION. Let me introduce the scenario: I have designed a double ...
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3answers
8k views

How are LEDs considered efficient?

I've always found circuits containing LEDs hard to understand, please bear with me. I know most people find it easy, but I'm confused by them so some of my assumptions might not be correct, please ...