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Questions tagged [dissipation]

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0
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1answer
24 views

Time it takes for B to go to zero with R and L given

Given that your solenoid has inductance L and resistance R with initial current I such that there is uniform B inside the coil, I would like to figure out how much time will pass before B goes to zero....
0
votes
2answers
58 views

LCD Backlight Control Circuit

I'm trying to control the back-light of a TC1602A-09T 16X2 Character LCD by using an output pin on a Teensy 3.2 microcontroller. This is the circuit I have at the moment: The LED- pin would be ...
0
votes
2answers
138 views

Heat dissipation zener diode and resistor

I have the following circuit When I am testing the circuit with 5V USB 3.0 power supply, the zener diode and/or resistor does not build heat up. Using the 18650 7.4V battery makes it build heat. The ...
0
votes
1answer
61 views

Dynamic power dissipation of a Cmos inverter with relation to it's geometry

I know that the dynamic power dissipation of a CMOS inverter is defined by the equation: Pd = (Cl)(Vdd^2)(fb). My teacher challenged us to find ways to reduce power dissipation besides the obvious ...
0
votes
1answer
115 views

Off-load voltage of wall-warts

I need to regulate an incoming DC supply from a wall-wart down to 5 volts. I'm experienced with designing power supplies with ordinary transformers. In this situation, the maximum voltage I can expect ...
0
votes
2answers
280 views

Help to calculate heat dissipation on plastic dual in line DIP package (DIP-8 opamp)

Question is about maximum chip heat dissipation (and not about efficiency or correctness of this design). Circuit is quite simple: put in parallel 30 Dual Opamps in 8 pin DIL package (i.e 60 opamps ...
14
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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 ...
12
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4answers
2k views

Book Suggestion - How to calculate the power dissipation of a BJT

I did a exam that asked for "power dissipation" of a given BJT circuit. The question was simple but my professor considered my calculation of dissipated power wrong, because my answer was \$P = V_{CE} ...
0
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1answer
754 views

Total power consumption in LTSpice

I know how to measure the average power dissipated on a component but I have a very big circuit with lots of components so I am looking for a short way to calculate the total avg power in the whole ...
0
votes
1answer
261 views

Power dissipation in a Darlington built with an optocoupler and NPN

I have implemented a PWM control over a relay from an Arduino. To isolate both circuits I have used an optocoupler 4N35 from Vishay. Since it cannot provide enough current flow to drive the relay, I ...
4
votes
2answers
327 views

Does a transistor/FET dissipate more power with a freewheel diode?

My question is: Does the transistor dissipate more power because of the freewheel diode? Ifso, why? simulate this circuit – Schematic created using CircuitLab
1
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3answers
57 views

Power used by a PLC for communication

I am working on a PLC (Programmable Logic Controller) that receives input from four pressure sensors (4-20mA) and a proximity sensor. Two of the outputs actuate relays. The PLC communicates via Modbus ...
17
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4answers
2k views

125 mW resistor subjected to 600 mW dissipation in professional safety system

The schematic below is the input circuit of a signalling PCB, which we buy from one of our suppliers of fire detection systems. Said PCB has to be built into a so called geographic evacuation panel ...
0
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2answers
478 views

Typical dissipation constant of average thermistor?

What is the typical dissipation constant of average thermistor? I.e. how much current I can feed to thermistor without significant self-heating? I know that I can measure exact value for particular ...
-3
votes
2answers
60 views

voltage-energy input and voltage drop energy taken away

i want to understand voltage. voltage across a battery is the energy per charge that the battery can provide. if we give more charge inside the battery we can get more overall energy in the battery ...
0
votes
2answers
160 views

MOSFET getting hotter than calculated

as the title said, I'm facing this problem. I'm controlling a Peltier element (91.5W at 15V, what should give us aprox. 4A at 12V) with two different MOSFETs: IRF3205 (Rds(on) = 8 mOhm) and FQP30N06 (...
0
votes
1answer
436 views

Heat dissipation Aluminum PCB

I'm not sure how to calculate the following. I want to SMD solder either 3 LEDs or 6 LEDs to an aluminium core PCB. The LEDs in question are PK2N (datasheet) and, according to the datasheet, the ...
5
votes
1answer
1k views

How to estimate the required PCB surface area for SMD power resistors

I am migrating a design from through-hole parts to use as many SMT devices as possible. There are 7- 2 Watt power resistors in the current design. These are metal-oxide resistors that have crimped ...