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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Given the surface area, volume, and temperature of an IC, can you calculate how much power is dissipated?

Assume the temperature of the IC is uniform and constant and the surface area and volume are known. Can you calculate from these values the power dissipated by the IC through heat? If not, what ...
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Power dissipation BJT transistor as voltage follower

Following the discussion from this thread I am finalizing my calculations. I am not sure that I am calculating the power dissipation correctly. Given the following circuit I need to operate the opamp ...
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Diode selection for step-down Converter

I have built quite some buck converters for ~3A@3-5V (~1MHz, 24V Input) and I always used schottky diodes due to their low forward voltage drop (and therefore low power dissipation during free ...
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38 views

SPICE IC model in-circuit power dissipation

I'm looking into a way to calculate the power dissipation of any arbitrary IC in circuit on SPICE. I eventually hope to create simple scripts that can list power dissipation of the device and ...
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217 views

Heat Dissipation Calculation for MOSFET

My challenge at the moment is dissipating 60A of load current through an array of MOSFETs. Here are my specs: No cooling fans Heatsinks allowed, if needed FET and/or heatsink cannot attach to the ...
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65 views

Possibility of dissipating 20 W via Nichrome wire safely

I am looking to use 1 foot (0.3 meters) of 32 AWG nichrome wire to dissipate roughly 20 watts of power. Assuming the wire was submersed in still transformer oil, would I be able to do this without ...
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40 views

Advice on a voltage measuring circuit

I've been working on a voltage divider circuit that will hopefully allow me to measure voltages between 0-60 kV DC (80 W) as 0-889 volts DC. The voltage divider section that is used to measure the ...
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50 views

Calculation of Power Dissipation of Memory ICs and Microcontrollers

Can someone tell me how to calculate the power dissipation of digital ICs like Nand Flash, QSPI NOR Flash and Microcontrollers? For Microcontrollers, we can get the power dissipation for GPIO like, ...
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110 views

Should thermal pads be connected to GND or not?

I'm creating a footprint for the TPS2141 (LDO and current limiter) and I wonder if the thermal pad should be connected to the GND plane or if thats a bad idea? Should it just have its own copper zone ...
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42 views

Calculating Power Dissipation in a Filter

Apologies in advance if my question seems too basic. I don't really know where to go from here. I understand that power can be calculated as P = IV or P = V^2/R or P = I^2 x R. I think I'm not ...
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116 views

Quiescent current vs GND pin current for Linear Regulator IC power dissipation

I want to confirm that, for a linear regulator IC, quiescent current multiplied by the input voltage accounts for the IC power dissipation(including drop-out voltage loss). I ask because the ...
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756 views

Heatsink on underside of PCB

I have prototyped some DC-DC converter modules, and they work well. However due to size, I don't have a huge amount of copper pour for them to dissipate their heat. I have used 2oz copper but the ...
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Transistor power dissipation rating

I'm trying to build the following circuit Except mine is a 24V ~20A (500W) motor, so I need to swap the components. I'm currently looking into transistors and I've stopped on the 2N6284 (NPN) ...
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74 views

Triac power dissipation

I'm driving a high power load with the BTA440Z (datasheet): line voltage is Vac = 230 AC, load power is P = 1.33 kW, thus load current is ~ I = 5.8 A. If i swap the load with another ...
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54 views

Thermal resistance Junction - Maximum Power dissipation

I want to understand the real meaning of the parameter 'Thermal Resistance Junction to Air (°C/W) to calculate the power dissipation. So for example if the value of this parameter is 250°C/W, should I ...
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POWER MOSFET - Thermal Design

i have some doubts about with this thermal design? first, the calculations and infos: My load (a motor) uses an average current of 7A, I could not measure the current peak at the beginning of the ...
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103 views

ESD Diode - clamping voltage

I'm trying to replace an existing ESD diode(PESD1CAN) in my application CAN circuitry due to some reasons, I've found an alternative ESD diode(RSB27C2), but compared to the diode that I already have ...
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LM317 - Calculate dissipation due to voltage drop

If I use a linear voltage regulator as LM317: Input voltage = 24 V Output voltage = 5 V (so a voltage drop of 19 V) Mean load = 480 mA (peak load = 700 mA) From the datasheet, I read that maximum ...
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703 views

How much power does LM7805 dissipate?

I'm using an LM7805 in voltage regulator mode. Vin is 15V Vout is 5V (regulated) The attached load draws 200mA How to calculate how much power the LM7805 would dissipate in this setup (and whether ...
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59 views

How do I treat this “lamp” to find power dissipated?

This is my circuit. I need to find the power dissipated by Vlamp. So the lamp turns on if the Vlamp is more than 2V. When the ...
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47 views

Determining Absolute Maximums for IC Output Current and Power

I'm having a small gap in understanding with a project I'm working on. The project is reliability related and requires looking at the absolute maximum values for some 54ALS family logic (Max Vcc, ...
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90 views

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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125 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
35 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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492 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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51 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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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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152 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 ...
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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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164 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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171 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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86 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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72 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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103 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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513 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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29 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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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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392 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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937 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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564 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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580 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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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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926 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 ...
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476 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 ...
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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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169 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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3k 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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40 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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77 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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426 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 : ...