North America Availability :( I have been looking for a retail vender in the U.S.A. with little success. Received a reply from Stella Lo at SeaSonic Electronics that the SS-350TGM is not currently in stock at SeaSonic California warehouse, only available as a sample from HQ in Taiwan. The SS-300GTW ...

I used the blue "EAR" grommets and 6/32 screws to decouple an exhaust fan on this pc7, but must take care with the compression of the grommets.

the PCB would be way cooler if you used SMDs and made it small enough to hard-mount on the fan header :) (just sticking 1" off the header) I did a PC board with Eagle using 1206 chip resistors and a FMB3946 {a 2N3904 + 2N3906 in an SSOT6 package} and it was only about 30% smaller. To get a signific...

You did not say where the the two capacitors were in the circuit, so I'm guessing they are the input and output caps for the 7805. From your description this is the circuit: pm.stacker_BJT.png If this is the correct circuit, then the BC337 is directly applying the PWM signal to the fan. As the duty ...

U1 is a TL431, Q1 is a PNP emitter follower, Q2 is a NPN emitter follower, Q3 is p channel FET. The current sourced from the base of Q1 is mirrored to the collector of Q2. The voltage drop across R4 drives the gate of Q3. Simulating with LTspice the output at 100% PWM is 11.9V into 60 ohms. Have a l...

Looks great pm.stacker.
Is the LED a voltage reference or for "bling"?

Looking to build a PWM to linear bridge that is small enough to reside on a 120mm fan.
Would like to brainstorm with like minded folks about circuits and PC board design.
It would be helpful if you understand in LTspice and Eagle.
Any one interested?

sthayashi

Would you be interested in collaborating?
Been working on a circuit with LTspice that has a P-channel FET for the output.
Would post, but ".asc" files are not currently allowed in this forum.

Regards

That is likely a XH connector housing. It is a 2.5mm pitch connector produced by several Asian vendors. Digikey sources them from JST. The two position housing [XHP-2] is digikey part number 455-2266-ND Tin plated crimp terminals, 22-28AWG for that housing are [SXH-001T-P0.6] digikey part number 455...

Great article Mike, very informative. I have a question. As you stated in the article, thermal systems (heat source, heat-sink and fan) are very difficult to model. As an example: heat-sink 'X' may out perform heat-sink 'Y' with a 137W input, but the reverse can happen at a different heat input. Thi...

It would be more involved than just moving the transistor. That circuit is using the PWM signal to turn the transistor on and off, so it would still corrupt the Tach signal. Not familiar with the adapter you linked to or if it's any good. You could build something like this and it would be about the...

To have the RPM sensor (Tach) work, the ground wire of the fan needs to be hooked directly to ground. The circuit in your post has the transistor between the fan ground and power ground, not so good for the Tach signal. What range of voltage do you want for the fan? Would say 5V to 11V be OK? How sm...

PWM is digital and gives power to the fan in pulses. In essence it turns the fan on and off very rapidly. It is very power efficient, but as with may things there are trade-offs. Some motherboards with the 4-pin fan CPU fan header only support 4-wire fans, so if you plug in a 3-wire fan you have no ...

Voted other, would like a review of 92mm and 120mm
Scythe Gentle Typhoons

As a starting point: Try a low pass filter and emitter follower buffer. I'm at a disadvantage, not knowing the input impedance of the control pin on your Delta fans. If the input impedance is ~10K this may be all that's required.

Have an ANTEC TPII-380 shell. Has the original fan, line cord connector and the bushing for the output cables. Is missing the on/off switch and the 115V/230V switch. The guts went to e-waste recycling some time ago. PM if interested.

Taking a page from BTX airflow. I am thinking the M/B is less likely to have a dead air zone with a fan pushing air over it, because the rotating flow from the fan outlet tends to stir-up the air column more than a fan pulling air over the M/B. Don't know if it will work. The NSK3300 has plenty of e...

http://s3.postimage.org/dJjSS.jpg http://s1.postimage.org/tUIor.jpg http://s4.postimage.org/cLIfJ.jpg New holes in bottom of chassis and tray modded for laptop HDD. M3, 8mm long by 5mm hex male/female standoffs are used to secure the HDD with the original grommets. http://s2.postimage.org/tkXAJ.jpg...

rivet Your best source for troubleshooting info would be the support section of the SpeedFan Home Page . On the face of it, could be that a device is accessing the SMBus at the same time that SpeedFan is loading. Try disabling SMbus access for SpeedFan. Select the "Configure" button, open the "Optio...

nemo For the EA-380, I suggest a fan that starts reliably at 4 volts, otherwise the fan won't start ruining until the PSU heats up a bit. Several posts in the general gallery have used the Noctua NF-R8. I used an Adda AD0812MB-A71GL, salvaged from a NeoHe that suffered an early demise, with good res...

Shaggy My apologies, I did not consider the graphics card could be using low side drive. If this is the case, using the divider, the signal would be 180° out of phase. That is 12 volts @ 0% duty cycle and 3.3 volts @ 100% duty cycle. If you use differential sensing, low side drive won't be an issue...

Shaggy
You are correct, the MAXIM circuit was designed for a 3.3 volt PWM signal, however you could add a voltage divider configured to divide buy 3.6 (100k and 39K) to scale the 12 volt signal to a 3.3 volt signal.
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trident

Shaggy Your question doesn't have enough information for a definitive answer. What do you mean by low frequency and 2-pin? I am going to guess that you have a controller that outputs high current (500 to 1000mA) PWM that is capable of directly powering a typical fan. If this is the case you may want...

Useful information about controlling fan speed. Maxim AN1784.pdf I do not wish to start an argument or claim there is only one best way to go. I offer this as another option. There are many ways to convert PWM to linear voltage, your design goals determine the best method for your application. If yo...

Greetings Hypernova The 2 amp limitation is because of the three pin fan connector {reference Molex 22-01-3037 and 80-50-0114}, with tin over brass contacts 2.5 amps is the max. current handling. Reviewing your project goals, "No more than 1V drop from the control circuits, range should be 5~11V", u...

Working on revised circuit, MOSFET selection not as critical(main requirements are Rds(on) @Vgs=10V: <100m Ohm and Vgss >12V). edit 18 Apr 2010: Experimenting with fixed integrator. The variable integrator has proven to be non-linear, due to a large difference in the charge and discharge currents an...

Greetings ctrler, welcome to SPCR!
What part of the chassis would you like to see in the new pictures?
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trident

Greetings There is a caveat to soldering in modern PSUs in that many if not all use lead free solder and it is best not to mix legacy tin/lead solder with the current tin/copper alloys. 96SC (SAC387) which also contains silver is a good lead free rework solder, however it is quite expensive. In my l...

Greetings mcmahad and EsaT Analog control will dissipate the excess voltage as heat, but the waste heat may not be as large as you may think. A brushless fan behaves similar to a fixed resistor, so the the current draw of the fan decreases with applied voltage. For a 12 volt fan with 0.3 amp running...

Things are progressing slowly as the current economic downturn is directly affecting me, have more time, but much less money. Modifications completed to date: Close front fan port with 3.2mm ABS sheet overlaid with AcoustiPack Add PC-60 HDD rack with suspension bungees and soft mounted updraft fan C...