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Questions tagged [fan]

A device that produces air movement by way of blades or surfaces attached to a rotating motor.

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1
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3answers
973 views

Big heatsink vs. small one with a fan

There's quite a bit of math to be done when you need to calculate a size for your heatsink. As there are many options to choose from if you don't know the size yet, is it just better to pick the ...
1
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2answers
362 views

Driving an LED from an 1.8V GPIO pin that defaults to “IN”

I have an EspressoBIN board, which has 1.8V GPIO pins with a max current of 8mA. I'm attempting to drive some status LEDs from them, and a 5V fan, so I'm using 2N2222s with 220 Ohm base resistors ...
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1answer
241 views

HVAC fan relay intermittently sticks closed; opens when touched

I have constructed a simple OR gate using two HVAC fan relays to control a 120VAC/1.5A booster fan for my home HVAC system. I have a zoned system, with multiple thermostats, but only one zone/...
0
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1answer
117 views

Add a LED and a resistor to a working circuit

We found, with my 6 y.o. kid, a 9V battery and an old CPU fan power supply fan, and we were happy to see the following circuit 1. working. Then he asked: "Can we add a switch and a LED?" For sure we ...
4
votes
1answer
118 views

Need to control fan speed at extremely low level [closed]

The application is to vent an electric BBQ smoker. I'll be moving to an apartment and have a serious pulled pork & pastrami addiction. I tried computer fans and 4" in-duct fan with different ...
3
votes
1answer
242 views

12V variable-speed fan as a function of temperature using 555 timer

I would like to turn the car fan into a variable-speed fan using a the analog temperature sensor of the car, and a 555 timer. While temperature decreases, resistance (of the sensor) increases. Can I ...
0
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2answers
2k views

Transistor use - Basic fan speed controller

Someone mentioned to me that they wanted to replace a fan switch with a potentiometer to adjust the fan speed. This seemed a reasonable request, and being eager to learn, I drew up a schematic using a ...
2
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4answers
7k views

Using 12V fans with a 24V PSU

I have recently acquired a 3D printer and have been experiencing all kinds of trouble with the fans used to cool the printer head, the parts and the controller board. The controller is a smoothie-...
-1
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1answer
77 views

Trouble understanding computer fan wires

I recently found a computer fan in my school electronics lab and I'd like to use it in reverse - make it spin the other way. The trouble is that I can't understand what wire does what, since the color ...
0
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2answers
131 views

Trouble finding how I can plug in this Molex connector from a Laptop Fan [duplicate]

I recently bought this fan, I am trying to power it for an external project that doesn't revolve around laptops; however, I don't know how to get power to the fan without cutting off the molex ...
0
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2answers
61 views

Can I replace a fan with a lower-rated fan? [closed]

I have an old RadioShack inverter / battery device that seems to have died because the fan seized up. The original fan is labeled DC 14V 0.09A. The battery in this unit puts out 16V according to my ...
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1answer
100 views

Trouble with the Cooling Power of Fans

Thank you for taking some time out of your day to read my question, I have improved the specifics of my question: I have a project in which I cool a very low power Peltier device (none of this ...
0
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2answers
2k views

How do I tell which wires are Red/Positive and Black/Negative on these fans?

thank you for taking the time to answer this question : Here are the fans in question... I only ask because I burnt both fans trying to find the right wires, so I guess I put the wrong wires on for ...
1
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0answers
476 views

DIY PWM Fan Controller; Speed changing too fast

I couldn't think of a way to explain all this in one line, so apologies for the slightly vague title. I've built a PWM Fan Controller for a DIY Laptop Cooling Pad Project. It theoretically works, and ...
0
votes
1answer
47 views

Fan controlled By heat. [closed]

I need to make a computer fan powered by 12v that turn on when the heat is like over 40 degree and to power off if the heat drops down. I asked in many Facebook pages and some told me i need a ...
-1
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2answers
67 views

Confused as to why one USB battery pack will run my devices vs why a wall wart will? [closed]

I am trying to run a 5 Volt 4 Amp Item off of a USB Power, and something went wrong today that I wouldn't have expected. For reference, I am using a USB cable capable of sending 2.4 Amps, and either ...
0
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2answers
489 views

Fan speed controller according to temperature using arduino [closed]

I am working on a project to control fan speed according to temperature using arduino, according to the above circuit all the connections have been made , but the speed of the fan does not change , I ...
0
votes
2answers
58 views

Confused on how to wire a Laptop Heatsink/Fan

thank you so much for taking some time out of your day to answer my question. I have bought this Laptop HeatSink/Fan combination and it comes with a molex connector at the end of the wire to attach ...
0
votes
1answer
299 views

Transistor Switch for my Raspberry Pi 3 FAN

Update 1 : After some help and advices from nice people here i'm going to use this circuit : http://everycircuit.com/circuit/5857347480322048 the 25 ohm resistance being the fan. I'm requesting ...
1
vote
1answer
128 views

Battery size to power a 240v 35watt fan for 12 hours and what size/ power solar panel to recharge it?

I'm a real novice when it comes to electrical engineering. Like a fish out of water. I want to create a self-sustaining fan for summer. I'm trying a fan that's 240V, 35W. If I was going to run it ...
2
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3answers
3k views

What mechanism controls a ceiling fan speed?

Are all ceiling fans AC induction motors? Since any ceiling fan can accept any off-the-shelf fan dimmer switch and any wireless remote unit that fits in the base, that means they've all got something ...
-2
votes
2answers
2k views

Can I connect 4 12v fans to 1 USB cable plugged into a wall? [closed]

I bought 4 computer case fans for a project I'm doing. I know how to wire just one fan to a USB plug that I put into my wall that makes the fan work. How would I go about connecting 3 more fans to ...
1
vote
1answer
464 views

12v PWM Fan Seems to Be Running Inversely of What It Should Be

I have a 120mm 12v Fan that is used on an Antminer S7. There are two fans on the antminer, and they both are controlled by the software built in. I had one fan break, so I replaced the fan with a ...
1
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2answers
2k views

control speed of 12v dc fan with thermistor

As a learning exercise, I am trying to control a 12VDC/0.18A computer fan with a thermistor. As I am planning the circuit (and I certainly can be wrong in my calculations), I plan to have a 12V power ...
1
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4answers
1k views

S8050 BJT is rated for 700 mA but gets extremely hot when powering a 12 volt 700 mA PC fan

I'm working on a project that requires a DC motor, so I salvaged a PC fan from an old computer. The model is AVC DS08025R12U. It needs 12 volts for maximum speed and is rated to draw 700 milliamps. I'...
1
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2answers
4k views

Can I run a 12v fan off of a 9v power supply for LED lights and are there any side effects

I have multiple (9v 1500mA to 9v 3500mA) LED light fixtures that I have tested chaining a single fan (12v 5.2w and 12v 0.16A fans) and they seem to work under the brief test with enough air flow for ...
-2
votes
2answers
338 views

Preventing a voltage drop using solar panel and fan

After failing to find an answer online I hope someone here would know how to solve n issue I have. I use a 12v, ~10w solar panel to activate a couple dc fans. The problem is that when activated, the ...
1
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1answer
134 views

Relay-controlled Fan Transient Question

Greetings guys and gals, I am seeing some odd behavior in my PIC-controlled circuit and need some help from the experts. I have a PIC18 at 3.3V turning on a bathroom vent fan via a relay. The fan ...
4
votes
2answers
2k views

Does a fan need a flyback diode?

I'm aware that inductive loads like relays need a flyback diode. Since a motor is also an inductive load, I'm inclined to put a reverse-biased 1N400x diode across the terminals of this fan. However, ...
1
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2answers
645 views

Designing a simple fan + resistor system for heating air

I have a research application that requires a steady supply of heated air. My current plan is to 3D-print a small tank (6" x 6" x 4") to which a muffin fan will be fastened. The fan will blow air ...
1
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2answers
1k views

full wave rectifier resistor place

Where is the best to place resistor in full wave rectifier circuit? What is the difference in usage of the resistors in these two circuits? (values are not precise) Three side questions: what about ...
0
votes
1answer
713 views

555 timer based PWM fan controller does not PWM

So I've made a PWM fan controller based on 555 timer, but it does not acturally modulate any pulses, the output is exactly the same as the input so the fan works but does not react to changes in pot ...
0
votes
1answer
522 views

Fan speed control - Voltage (0-5V) to PWM (0-100%) with minimum value

I need to control 12V fans (w/ PWM so 4 pin) with a laptop motherboard which originally had 5V fans (3-pin only so voltage-controlled), so I want to: use external supply of 12V (or internal from ...
0
votes
3answers
2k views

connecting a LED to a PC case fan header

On my motherboard (ASRock B150M Pro4S/D3) i have an unused 3-pin case fan header. Can i use it to drive a single LED with only a resistor in series? The fan can be configured in the BIOS to change ...
3
votes
2answers
214 views

Waterproof Fan Failing In A Chamber With 100% Relative Humidity

So I've built a aeroponic tower that uses an ultrasonic atomizer instead of spray nozzles. This approach is called "fogponics" across the hydroponic community. My Problem is that I have to run a fan ...
57
votes
9answers
28k views

Fan and heatsink - suck or blow?

This question covered it for enclosures. However, from the point of view of the fan attached to a heatsink does it matter whether air is blown through the fins, or sucked through the fins. In other ...
4
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2answers
907 views

Solar powered mini fan

for a school project I have to do something that needs the environment to work, my plans are to make a solar powered mini fan, now my question. How can I make that the fan ( 6v dc motor) keeps working ...
1
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2answers
1k views

reducing a 12volt fan speed

I bought a 12volt, 80 watt aftermarket fan for a car. What I'm making is a portable swamp cooler for my tent when I move to AZ this summer. I plan to charge a 30 amp, deep discharge trolling motor by ...
0
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3answers
1k views

power 12v fan using laptop charger while running laptop

I have a laptop with partially damaged internal fan. Dont want to buy new one. I am thinking of swapping the internal fan to a 12V fan. The 12V fan I have can fit as it is small. Internal fan is 5V. ...
1
vote
1answer
576 views

Powering thermoelectric cooler and fans with 12V input

I was considering a project with a thermoelectric cooling module rated 60w and so obtained an AC power supply of output DC 12V and 4.16A. I'm very new to electronics so excuse me for the basic ...
0
votes
1answer
2k views

How do you wire a CPU fan to an external 12v PSU

I have a CPU fan that I'd like to wire to a 12v PSU. I have tried following the advice here and here, and connected the black outside wire on the fan to my PSU -V, and then connected the next, red ...
0
votes
2answers
157 views

Can I control an extractor fan with a ceiling fan controller

Help needed please on controlling a extractor fan... I've design and having built a flush ceiling kitchen extractor fan. I'm planning to use a Vent Axia ACM150 (50 Watt) inline fan But trying to ...
0
votes
1answer
231 views

Rig a BJT to drive a fan

I wanted to see if i could use a BJT to power a small pc fan. I have a potentiometer into the base but how would I wire the fan so that depending on the base current it would adjust the current to the ...
0
votes
1answer
942 views

Calculating the value of the resistance for controlling the speed of AC fan

i have an ac fan that i would like to control its speed i am a bit new in this field so please bear with me i had the idea of fixing 3 speeds with 3 switches one for each speed: (25% 50% 90%), ...
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2answers
796 views

PCI Express powered fan controller

I would like to make a PWM fan controller that uses a 555 timer and be placed in a Gen 2 PCI Express x1 slot, while pulling the power from the slot as well. I'm not looking to send or receive any ...
-4
votes
1answer
449 views

controlling ceiling fan speed to minimal [closed]

Currently, the fan is still fast for me on number 1 speed. Is it possible and how to reduce this speed further using any device.
1
vote
1answer
1k views

PC Fan PWM signal circuit using 555 timers: Can anyone explain this circuit to me?

I'm looking at building a 4-wire PC fan PWM circuit. The goal of such a circuit is to send a PWM control signal to a 4 wire PC fan, so that the fan can modulate it's speed (NOT to pulse the 12V supply)...
1
vote
2answers
9k views

Safe connection of a 4pin Fan to an Arduino

I'm aware that a very similar question has been asked here before: https://electronics.stackexchange.com/questions/91015/how-connect-a-4-wire-fan-to-arduino-and-control-the-speed However, upon ...
0
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4answers
776 views

Will a buck converter drain 2 X 9v batteries with no output load

I'm currently building a circuit used in a personal portable cooling system. The fan is a 12v turbine fan (0.1A) My plan is to use 2 9v batteries in series to give me 18v then use a buck-converter ...
-4
votes
1answer
279 views

CPU fan motor to power a small light bulb [closed]

Have you all heard about the cpu fan as a motor, that one with magnets, would it really work? And how fast does it need to spin to generate enough electricity for a small light bulb?