Simple automatic regulator

Simple automatic regulator

Here is a simple scheme for automatically turning on the fan and controlling its speed depending on the temperature of the sensor. This simplest circuit, consisting of only two elements, can be used in your amplifiers, power supplies, computers, etc.
Simple automatic regulator

Operation of the automatic regulator circuit


The LM35 chip is used as a temperature sensor. She looks like a three-legged transistor. The output voltage of this sensor is linearly proportional to the temperature in degrees Celsius. That is - 10 mV / degree Celsius, for example, if the temperature is 45 degrees, then the voltage at the sensor output will be 450 mV or 0.45 V.
The base of the transistor BC548 NPN structure is connected to the output of the sensor. From the characteristics of this transistor it is known that it begins to open when the voltage between the base and emitter exceeds 0.4 V. Consequently, the fan will begin to rotate when the sensor temperature exceeds 40 degrees. And when the sensor temperature exceeds 60 degrees and a voltage of 0.6 V appears at the output, the transistor will open completely and the fan will rotate at full power.
Simple automatic regulator

This is such a simple job and such a simple scheme.
If the circuit operates unstable or intermittently, I recommend connecting a 0.01 µF capacitor directly to the power legs of the LM35 sensor.
Instead of a computer cooler, you can also turn on a low-power brush motor, but then you need to insert a resistor with a resistance of 10-50 Ohms in series with it.
come back
Comment
  • bowtiesmilelaughingblushsmileyrelaxed relaxedsmirk
    heart_eyeskissing_heartkissing_closed_eyesflushedrelievedsatisfiedgrin
    winkstuck_out_tongue_winking_eyestuck_out_tongue_closed_eyesgrinningkissingstuck_out_tonguesleeping
    worriedfrowninganguishedopen_mouthgrimacingconfusedhushed
    expressionlessunamusedsweat_smilesweatdisappointed_relievedwearypassive
    disappointedconfoundedfearfulcold_sweatperseverecrysob
    joyastonishedscreamtired_faceangryragetriumph
    sleepyyummasksunglassesdizzy_faceimpsmiling_imp
    neutral_faceno_mouthinnocent
5+two=
Comments (2)
  1. mstr.drv
    #1 mstr.drv Guests November 12, 2017 04:00
    3
    complete nonsense.
    The circuit on the field switch and thermistor keeps the temperature +-2 degrees Celsius.
    1. Guest Alexander
      #2 Guest Alexander Guests 9 March 2019 14:02
      3
      I decided to solder.