24
votes
Accepted
Why does my MOSFET always burn?
It looks like you have two problems here.
Your steady state losses are excessive; you say there's no heatsink, but 1.5 W (incidentally, your current of 1.5 A will actually result in a power loss of ...
- 19.5k
12
votes
Why does my MOSFET always burn?
Do you have any cooling or heatsink on the MOSFET?
The on resistance of the MOSFET will cause it to dissipate ~500-600mW of heat. The MOSFET has a thermal resistance of junction to ambient of about ...
- 26k
9
votes
Accepted
What kind of component is this resistor-like part?
It's a 10,000 pF (0.01uF) axial-lead ceramic capacitor. It should measure open circuit on a resistance range of a multimeter and close to 10nF on a capacitance range.
Replacing it with a radial leaded ...
- 328k
6
votes
Accepted
Active PFC with discrete components
A person after my own heart!
Some tips:
You don't have to use full op-amp sections everywhere you need an amp/comparator. Example: the oscillator can be 3-4 transistors. This will be far easier to ...
- 1,035
5
votes
Why does my MOSFET always burn?
If one changes the optocoupler, it can be "better" ...
And adding a resistor (base Opto to ground) ... one can see the drastic diminution of the power dissipated by MOSFET ( from 26 W to ~3 ...
- 3,916
4
votes
Accepted
What does this component on a +12V wire do?
That is a surface mount fuse. From the code marked on it ("P"), it would be rated for 3 amperes.
Replace the surface mount fuse with a 3 ampere fuse or replace the board with a fuse holder ...
- 57.7k
2
votes
Accepted
How to distinguish which buttons have fixed on/off positions similar to a flashlight button?
When looking at switches and buttons, you'll find a wide variety of terms to describe the switch action. Further, those terms will vary a little bit based on the type of switch as well. For example, ...
- 27.1k
2
votes
What does this component on a +12V wire do?
It is a surface mount fuse, mounted on a small PCB for connecting it to wires.
- 87.4k
1
vote
Picking components
Stealing schematic from there...
The boost converter has few parts. Getting any of those wrong will wreck it though.
Input cap
Inductor
Switch FET
Diode or synchronous rectification FET
Output cap
...
- 57.7k
1
vote
Dual LED Configuration
You can buy a 4-pin (most likely only SMT) dual red/green LED and make either of the two possible anode-cathode connections yourself. Or connect them as common anode or common cathode.
There are many ...
- 328k
1
vote
Parts shortage, no stock, what now? (canonical reference question)
I have noticed two drastic changes in my workflow compared to <2020:
I used to do: Simulate, Schematic, Layout, Order. Now I do Simulate, Check stock, Order, then only start on the project ...
- 10.3k
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