T&L Publications

Thanks Bigglez and trident, That is all correct. The LM4040C30 is fine with me. BTW this circuit has been breadboarded using the AD822 op-amp and the LM393 comparator. Outputs are pretty much identical showing about the same amount of slew time or distortion. I have also configured the circuit using...

Miguel,

From your description it sounds exactly like the maxx-com to me. Did you read this link?
Mhttp://www.maxx-com.com/MaxxComandtheSea.htmlaxx-Com.

Steve G.

trident, Seems like the specs keep changing as this is developing. So you have a working output circuit that needs a 0 to 3 volt input. Again, why not use a buffer amp for the input circuit, in this case a dual buffer. Eliminate all the resistors and transistors. The 3.3 volt regulator will set the ...

trident, If the level of the PWM signal is set by the MB then I see two options. Rearrange the circuit with the amplifier up front with a gain of four. The output will be limited by the 12 volt supply. Or you could use a comparator with say a 2.5 volt reference. The variable DC output is controlled ...

trident,

I don't see why it's necessary to use a comparator. Since the PWM signal is converted to DC in the low pass filter all you need is buffering and an amplifier.

Steve G.

I don't think it's changing the wavelength. Any thing white reflects all colors. The infrared LED probably has a small amount of output in the red/orange band that shows up when held next to the paper, same for the ultra violet in the visible blue wavelength.

Steve G.

CJensen,

Could add a switching xistor to isolate the pulse circuit.

Steve G.

grant fair,

I would try it using two of the IRFP460. Shouldn't need to change any resistor values on the gate drive as long as Vgs is at least 10 volts and doesn't exceed it's 30 volt rating. If the mosfets are running "hot" then install the third one.

Steve G.

trident, Thanks for the explanation. So if I understand correctly, you are trying to convert the PWM signal from the mother board to a variable DC voltage to drive the three wire fan. What is the minimum DC voltage required before the fan stalls? Are you using the "tach" output for any kin...

trident,

Something doesn't sound right here. Can you or someone else explain to me why you are trying to control a three wire fan with a four wire header?

Steve G.

psycho,

The SCR and TRIAC are the solid state replacement. Did you read the whole article?

Steve G.

CeaSaR,

You would need to drop the value of R4 to maybe 1K if using your origional circuit. May not make much difference since the only circuit running off the 9 volt battery is the preamp.

Steve G.

MrAl, That was a long post :shock: ! Are you sure one of those bolts didn't fly off and hit you in the head! :smile: Just kidding. I remember a similiar situation installing a LCD TV where I thought the screws were the wrong size for the same reason. Noticed on another post about a death in your fam...

jimandy, Correct, it's usually better to eliminate the cause then try and cover up. You could try one of those 12 volt in-line power filters, something like the one in the link below. There're mostly just a couple of capacitors and a coil. Steve G. http://www.europeanautosource.com/product_info.php?...

MrAl,

That's correct there is the fine pitch M4x0.5, but if the instructions say "M4" only then the .7mm pitch should be correct. From what I've read if the pitch is not stated then the normal coarse thread .7mm applies. Just get both, got to be one or the other right?

Steve G.