Can I use the fan control for the LK204-25PC on the LK204-25

|XLM|Phoenix · Post by **|XLM|Phoenix** » Mon Nov 19, 2001 4:47 pm

Well i have a LK204-25, so i would like to use the fan control on my PC.

Or can i 'transform' it into a LK204-25PC? Cause they look like very similar...

_________________
"Please, be gentle: I'm french and my english is not perfect"

<font size=-1>[ This Message was edited by: |XLM|Phoenix on 2001-11-19 16:47 ]</font>

<font size=-1>[ This Message was edited by: |XLM|Phoenix on 2001-11-28 06:17 ]</font>

Post by **Henry** » Tue Nov 20, 2001 5:04 pm

We will post something very soon with all kinds of information on this subject. Stay tuned...

|XLM|Phoenix · Post by **|XLM|Phoenix** » Wed Nov 21, 2001 5:23 am

Many thanx!!

|XLM|Phoenix · Post by **|XLM|Phoenix** » Tue Nov 27, 2001 4:55 am

Er......

I forgot to ask: when will you published it?

(and if there anybody here who speak french 'cause it will be more easy for me! )

Post by **Aniso** » Tue Nov 27, 2001 1:09 pm

These schematics are given with little explaination at this point. The assumption is that if you can read the schematic, you probably know enough to make sense of it rather than just trying to copy it in ignorance. Please know what you are doing for you will find little mercy if something smokes.

I believe that Henry is intending to make a web page which goes into more detail and says which model's GPOs are which.

Post by **linear** » Tue Nov 27, 2001 1:42 pm

Circuit three gets my recommendation (I hate relays) but can a 2N3904 handle fan current? I don't have the datasheet handy, but I'm thinking I recall 200mA collector current, which will suffice for only the wimpiest of fans.

Luckily, any NPN would work there, and even a Darlington pair for robust current characteristics. Just sub a beefier transistor for the 3904.

Post by **Henry** » Tue Nov 27, 2001 1:47 pm

The 2N3904 transistor is just an example. You could use anything you want, like the 2N3055 for example.

chiark · Post by **chiark** » Wed Feb 06, 2002 9:03 am

Any update on this at all?

Post by **Henry** » Wed Feb 06, 2002 10:08 am

Coming soon, there were a few little technical difficulties...

mhains · Post by **mhains** » Thu Feb 21, 2002 12:14 pm

I built the third circuit, and it didn't put more than a few volts through to the fan. Not enough to even turn it. Attaching an LED to the connection showed that it was likely about 3-4 volts.

A friend ran your third one through a circuit simulator, and says:

With the component values given, the transistor will only allow 68mA to flow (less then 1 watt of power at 12V)
If you reduce the value of the resistor to 1KOhm, the transistor will allow 170mA to flow (just over 2 watts to the load)
The maximum current through this transistor is 200mA, which is not a lot. The solution is to either use a relay or a different transistor that is capable of higher current.

Still trying,
Michael

Post by **Henry** » Thu Feb 21, 2002 12:37 pm

try the 2N3055

mhains · Post by **mhains** » Thu Feb 21, 2002 6:48 pm

Grabbed a 2N3055 on my way home from work -- man, it's huge -- and it only has two pins. Any suggestions?

Post by **Aniso** » Mon Feb 25, 2002 3:59 pm

Yes, if it has just 2 pins, then it is probably a D-Pak type. This type is intended to be soldered to the heat sink, so you will have to think about that. You need a heat sink.

The "tab" is actually the third pin. It is the collector.

Aniso

On 2002-02-21 18:48, mhains wrote:
Grabbed a 2N3055 on my way home from work -- man, it's huge -- and it only has two pins. Any suggestions?

Detritus · Post by **Detritus** » Sun Apr 07, 2002 4:18 am

I was pointed at this thread by Henry (cheers!

). I'm trying to build a relay circuit for my VFD so that I can use it to power a couple of cold-cathodes on and off.

I think I understand the diagram (3rd). You've got a diode wired in parrallel with the fan. A 4.7k resistor wired in between the GPO and a transistor which is switching voltage to the fan...right? I've had a look at maplins for a transistor that will handle 500ma of current on the fan side (500ma is erring on the side of caution, a cold-cathode uses 350ma) but their transistor section confuses the hell out of me. Can someone suggest an appropriate transistor, preferably one that doesn't need soldering to a heat sink? I'm thinking that a BD135 or a BD139 would work? Also, can anyone recommend a good book for learning electronics. I've done some (very) basic stuff like build a 12v/7v switching baybus with bi-colour LEDs but that's about the full extent of my electronics knowledge. I'd like to work through a book that teaches electronics from first principles with practical examples/projects...can anyone recommend anything? I've done the usual search on amazon but everything seems to be aimed either as reference work for schools or at those who already have a modicum of electronics know-how.

Thanks,
Detritus

|XLM|Phoenix · Post by **|XLM|Phoenix** » Sun Apr 07, 2002 2:25 pm

Whoa...

Sorry for no response, but i have a lot of exams!

Thanx to all....

..... but today my MO broke up.

After a power cut, the MO doesn't response any more.... the back-light is on, but there no signal...