which AC adaptor okay?

[Star-flog]

Consider to DIY PC fan and which of the following adaptor can be used? (as photo). Normally, for 1 PC fan, how many mA per unit? Any advice will be appreciated. Thank you.

[|squee|]

I'm using 12V DC, 350mA rating for my DIY fans. The adaptor powers two standard sized computer fans, so I think the one on the left in your picture should do it.

[Star-flog]

I'm using 12V DC, 350mA rating for my DIY fans. The adaptor powers two standard sized computer fans, so I think the one on the left in your picture should do it.

The one on the left has got only 200mA, enough for 2 PC fan? (if 1 PC fan needs 140mA). Any 9V PC fan in the market? If so can use the one on the right.

[mc2310]

PC fans are usually 12 VDC or 5 VDC. The one on the right is 9V AC output, can't use for most fans.

For 12 V fans, you have a wide range to choose from: I've seen 0.03A to 0.3A; The higher the current rating, generally more powerful BUT more power consumed, and noiser because of higher fan rpm. Do try to get one with fluid bearings to reduce the whirring sound.

Hope this helps

[vinz]

1. Make sure the voltage matches. Do NOT add the voltages together. I.e. if all you fans are using 12V, then make sure the adaptor outputs 12V.

2. Add the fan ampheres together and make sure the adaptor output exceeds the required input by 30%. This will ensure the life of the adaptor and prevent overheating. From asking around, I'm told that the power usage will only be what the fans pull, not what the adaptor is rated at.

[tawauboy]

normally, pc fans are 12v. you can still run it using 9v but it will be slower.
for current, vinz's advice is correct.

[Star-flog]

normally, pc fans are 12v. you can still run it using 9v but it will be slower.
for current, vinz's advice is correct.

Thanks for a good advice both Vinz and tawauboy..

The reason I asked because I've quite a few 9V AC/DC adaptor at home, and won't want to spend extra money. Based on your advice, I guess if 9V AC/DC adaptor for PC fan 12V is okay. The result is fan speed a littel slower but it's perfectly alright. As long as the PC fan will not 'die' prematurely, I mean give a lot of problem later.

Thanks a lot

[vinz]

In my experience, it's not the fans that die prematurely... it's the adaptors, especially if you run them 24/7. They literally die on you. I.e. their power drop so much they can't even start the fans. To prevent that always make sure you exceed the expected ampherage required by 30% or more.

Tawauboy, if a 12V fan is powered by a 9V adaptor, will the amphere of the fan remain the same?

[tawauboy]

vinz, let me check it out first.

when voltage is reduced to 9v, the current drops too.
based on a 12v 120ma fan, the current at 12v is 80ma and at 9v it's 60ma.