Energy Leak Detector


Posted on Feb 7, 2014

This sensitive circuit is basically a comparator, detecting very slight temperature changes in respect to the ambient temperature. It was primarily intended to detect draughts around doors and windows that cause energy leaks but can be used in many other ways, when a sensitive temperature change detector is needed. Two LEDs are used to signal if t


Energy Leak Detector
Click here to download the full size of the above Circuit.

he temperature change is pointing above (Red LED) or below (Green LED) the ambient temperature. IC1 acts as a bridge detector and amplifier: its output voltage raises when temperature increases and vice-versa. This happens because the n. t. c. resistor R2 reduces its resistance value as temperature increases and vice-versa, therefore unbalancing the bridge formed by R1, R2, R4, R5. IC2A and IC2B form a window comparator and R8 is the sensitivity control. Before starting a measurement the circuit must be balanced by means of R1 in order to obtain that both LEDs are off. If R8 is set to zero resistance the circuit sensitivity will be at maximum and one of the LEDs will illuminate when a very slight difference in temperature will be detected. As R8 value is increased the circuit sensitivity will decrease. IC1 acts as a bridge detector and amplifier: its output voltage raises when temperature increases and vice-versa. This happens because the n. t. c. resistor R2 reduces its resistance value as temperature increases and vice-versa, therefore unbalancing the bridge formed by R1, R2, R4, R5. IC2A and IC2B form a window comparator and R8 is the sensitivity control. Before starting a measurement the circuit must be balanced by means of R1 in order to obtain that both LEDs are off. If R8 is set to zero resistance the circuit sensitivity will be at maximum and one of the LEDs will illuminate when a very slight difference in...




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    PCBoardMaker3
    Digital Levels Scope Displays 2 Logic Signals On 1 Scope
    tune coil
    Stepper motor controller - Driver circuit with circuit design
    gic
    PIC-based PSK31 MedFer Beacon
    Simple Morning Alarm Circuit Using LDR and UM66
    FOUR STATION TWO WAYl



    Top