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12 votes

My IRL540N is smoking

At 7A, and assuming you are supplying at least 5V Vgs (Which is where the on state resistance is specified), I make the power dissipation about 5 watts, so you will want a small heatsink to keep the ...
  • 16.5k
6 votes

My IRL540N is smoking

Look out also for temperature coefficient of Ron. If you get a MOSFET whose Ron increases with temperature and you don't drive it hard enough on or give enough cooling, this can cause magic smoke very ...
  • 5,653
6 votes
Accepted

My IRL540N is smoking

When do I know it's best to replace it? After it smoked, it's necessary to replace it. See the "Absolute Maximum Ratings", first page of the datasheet. You've clearly exceeded that maximum ...
5 votes

How does putting an LED in parallel with an 8-bit computer load affect the voltage/current of a circuit?

I agree with everything Jasen said, but I would add (stress?) that this circuit demonstrates extremely bad practice. The danger is remembering this circuit technique without remembering its ...
  • 14.5k
7 votes

How does putting an LED in parallel with an 8-bit computer load affect the voltage/current of a circuit?

You're right that the LEDs will limit the voltage to about 1.8 to 2.2V and the only current limit is that inherent in the outputs of the chips driving those pins. But It's all TTL, so asnthing above 1....
  • 29.7k
3 votes

How does putting an LED in parallel with an 8-bit computer load affect the voltage/current of a circuit?

You should maybe ask Ben Eater about his circuits. We have not checked if the circuit matches the schematic or if that is just a block diagram and not the actual schematics. We also don't know the LED ...
  • 109k
2 votes

How does putting an LED in parallel with an 8-bit computer load affect the voltage/current of a circuit?

The highest voted comment, from Jason Smith, under the video points out this issue: NOTE! Watch your forward voltage drop on your LEDS(they act like a voltage divider*). I needed to add resistors to ...
  • 1,792
1 vote

How does putting an LED in parallel with an 8-bit computer load affect the voltage/current of a circuit?

Do not do that! Always use a resistor in series with an LED to limit the current. (Anything between 330 Ohm to 2.2 kOhm will work there.) Once you do, your question becomes moot.
1 vote

Torque to FOC Iq current conversion

It sounds like your expectations are correct, and you did what I would have done. Just to be sure let me run through it. 25.5 mNm/A implies .0392 A per mNm. So if you want 10 mNm, you need to set Iq ...
  • 28.6k
1 vote
Accepted

Why are my transistors failing?

This has turned into a wild discussion in the comments section but an extremely helpful one to me! Nevertheless, to answer the actual question for any future readers, the MOSFETs were most likely ...
1 vote

Why are my transistors failing?

This has many of the earmarks of a grounding problem. It is imperative that the power section be somewhat isolated from the signal circuitry. Try redrawing your schematic to resemble the actual wiring,...
  • 4,632
1 vote

Why are my transistors failing?

Note that the schematic lacks an important thing ... When one uses "paralleled" MOSFETs (not "paired"), current sharing is "imperatively" needed ... I did so for a "...
  • 9,644

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