# Tagged Questions

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### How to choose correct resistor with proper wattage and ohms for 6 leds connected in a serial circuit?

Let's suppose I've six LED lights with each 3.2 Volt and 20mA and all six of them are connected in one serial circuit. I know there is better setup but for this I'm using this circuit setup. I'm ...
2k views

### Is it possible to calculate how much heat dissipation and temperature rise will take place in a resistor

Suppose I have a 100 mAh battery at 20V. I connect a 1000 kohm resistor across it. How much heat will be generated and how can I find the temperature rise in the resistor? As the battery operates I ...
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### 5V Regulator Power Dissipation

I am using a 5V regulator (LP2950) from ON Semiconductor. I am using this for USB power and I'm feeding in 9V from an adapter. USB requires maximum of 500mA right? So the maximum power dissipation in ...
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### Overheating Problem?

I have almost no electrical experience, so I apologize about the simplicity of the question in advance. I have 4 resistors a diode and a transistor in a 22mm x 14mm x 8mm enclosure. My concern is that ...
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### Is CPU/GPGPU heat dissipation quadratic in clock frequency?

In the following article on overclocking a Pentium from 1GHz to 5GHz using liquid nitrogen: The 5GHz Project, there is an assertion that "Heat dissipation rises exponentially during extreme ...
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### MOSFET heat calculation question

I am using the FQP30N06L MOSFET. http://www.fairchildsemi.com/ds/FQ/FQP30N06L.pdf As far as I understand the data sheet, if I connect 5V to the gate and run 2A through drain to source then with a ...
224 views

### Would replacing a resistor by another one of identical value but higher power rating affect the working of a circuit?

The schematic recommends using 20 Ω 1W as collector resistance. What I have at hand are two 10 Ω rated for 10W. I'm guessing the change should be acceptable ... What difference would it ...
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### Wattage calculation for resistors in series

I need the formula for calculating resistor wattage when the resistors are in series. For example, say I have 3 1/4 watt 10 ohm resistors in series. What is the potential power dissipation for the ...
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### Can a soapbox-sized device dissipate 10-15W of heat? If yes, how?

Some time ago, I built a soapbox-sized battery testing device. One of its functions was to discharge batteries at a specified current, and it handled most of the common battery sizes well, but its ...
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### MOSFET for PWM application

I'm designing an application where a power logic level MOSFET is driven using a 5V PWM signal at 20kHz. The drain current will be approx. 10A and the voltage of the load 12V. I looked into the ...
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### How many watts will the resistor in this naîve PSU dissipate?

One would be inclined to think the average current on resistor R would be exactly the same as in the load L, but I'm not so sure of that fact, due to the effect of the (big, 1000uF+) capacitors. ...