Fan control circuit
Fan Control Circuit May 18, 2010 ... Here is a simple circuit based on two transistors that can be used to control the speed of a 12 V DC fan depending on the temperature. ...
Fan Controller by 741 The amplifier gets quite hot while in use, so decided to use a fan to cool it. The fan, however, adds a lot of noise. To get the best of both worlds, I thought I’d turn the fan on only when required. The circuit shown uses two forward-biased diodes, one as a sensor diode (at JP2) and the other as a reference diode (D2). The small difference in forward voltage drop is amplified by IC1 and used to drive T1. T1 turns on a fan when the temperature on the reference diode exceeds that at D2. D1 prevents inductive kickback from killng T1....
Processor Fan Control Fans in PCs can be objectionably loud. In many cases, the amount of noise produced by the fan can be considerably reduced by lowering its speed. Although this will decrease the amount of cooling, this need not be a problem as long as you don’t go overboard with slowing down the fan. Particularly with older-model processors,...
Heater Fan Controller by PIC12F675 A PIC12F675 provides all of the necessary functions. It reads the (10k) linear potentiometer and generates appropriately timed pulses to control the DC motor running the fan. The extreme low position cuts the power entirely.The circuit is relatively simple. The wire to the blower motor (either high or low side) is cut and connection is made to the circuit with the more positive side at the top connection....
DIY Dual Fan Controller Project The project helps you control two fan’s to cool whatever you need. It works by cooling with the first fan when the sensor detects a user adjustable temperature, and it turns the second fan on, when the temperature exceeds 5 degrees over the user adjusted temperature....
Temperature controlled Fan 12V dc Requested by some correspondents, this simple design allows an accurate speed control of 12V dc fan motors, proportional to temperature.
A n.t.c. Thermistor (R1) is used as temperature sensor, driving two directly coupled complementary transistors wired in a dc feedback circuit.
An optional circuitry was added to remotely monitor fan operation and to allow some sort of rough speed indication by means of the increasing brightness of a LED.....
Three channel fan speed controller for PC Jos van Eijndhoven have designed a 3 channel fan motor controllerbased on PIC 16F676 microcontroller. Mcu reads temperature from sensors and outputs PWM modulated signal to each output so the speed of fan is controlled accordignly. Three on board potentiometers controls the start up temperature for each channel. ....
Thermal Fan Controller by IC 741 and Diode The controller uses one or more ordinary silicon diodes as a sensor, and uses a cheap opamp as the amplifier. I designed this circuit to use 12V computer fans, as these are now very easy to get cheaply. These fans typically draw about 200mA when running, so a small power transistor will be fine as the switch. I used a BD140 (1A, 6.5W), but almost anything you have to hand will work just as well.....
