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What kind of ICs are these?

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New Member
I was taking apart a Dell power supply that I accidentally broke and I came across some ICs and I was just wondering what they do and if I can use them for anything.

# of Pins = 8
The logo is "ON" with a circle around it.

# of pins = 20
The logo is "ST"

I also come across what i think are capacitors. They are small and are blue. There are quite a few of them and some are yellow also. All have #s on them some are different some are the same. For example one reads "104" What does this value mean? 104 Farads?

Thanks for the help.


New Member
hahahahah 104 farrads would kill the world hehe

the first 2 digits are the value
the last digit is the multiplier

104 means 10 (first and second digit) + 4 zeros
=10 + 0000 = 100000 pF

this gives the the value in pF, but you would generally convert this to .1uF

this should help


good luck


New Member
I took apart a dell power supply too(a 224w power supply from an old p133).
The main switchmode transistor in an IGBT rated for 20A, 900v in a TO-3 case.
There are 2 680uF capacitors, compared to 2 470uF in most PC power supplies.
You really don't want to mess with those boobies(my friend Caitlin Williams got a shock from an unplugged fluorescent lamp that caused her to wet herself(lamp contains 1 220uF))!
I have charged a 330uF capacitor to 100v, then discharged it through a coil to magnetize a screwdriver(made one very loud pop, and it spot welded the coil to the terminals).
On the secondary side, there are MOSFETs used as rectifiers.
The design seems to use a flyback converter to generate 12v, then step this down to 5v and 3.3v with buck converters.
After taking apart the power supply and reverse engineering it, I conclude that dell is the Britney Spears of power supplies(I have heard on [H]ardforum that the 250w dell power supplies(like the one I have in my computer) are really 345w!).
I am running the following on a 250w dell(the Britney Spears of power supplies):
Pentium 4 2.4GHz
GeForce 4 MX 420 w/ 64MB RAM
48x24x48x CD-RW
50x CD-ROM
2x 7200RPM 60GB HDs
Voltages(measured with radioshack DMM):
12v: 12.05v
5v: 4.99v
3.3v: 3.30v


New Member
Thanks for the info, it helped allot!

got a few questions about reading capacitors.

I have a bag of ceramic caps.

they read 200K Z5P, 220k, .001M, 331, KCC CL -90

some others i have read 500K, E 182M, 223 z 098, Z5U .02M 100V, .02

I am unsure of how to read some of these. in a book i have it says that "K" means 1000 and "M" means 1000000. so how would that work with these caps. That link you gave me says those letters mean something different. if they do then how do i read the 200K, .02, and the .001M capacitors?

also does it matter is some of the caps only have 1 of the numbers underlined or have non of them underlined? like 473?

thanks. lol sorry for the novice questions. :oops:


New Member
anyone please?

is a .001M capacitor a .001 Micro Farad one? and is a 200k capacitor a 20pic farad? or am i reading them wrong? thanks.


Active Member
Yes, .001M is 0.001 mikrofarad = 1nF. The letters give the voltage.
200k is 200pF
473 is another coding system, same as SMD resistor code: the first two digit is value, third digit: number of zeros.
47000, dimension is pF. 47nF
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