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:

New Circuits

.

 


Popular Circuits

Precision-one-shot
Low-frequency-tachometer
Electronic Mini Projects
H-bridge circuit
Gray Projects
audio graphic equalizer circuit
Geomagnetic field detectors
Touch Volume Control Circuit
100 MHz frequency and period counter using the Intersil ICM7226B 40 pin DIP
Stage VI Mixer
Infra/radio remote control encoder/decoder with PIC
F007 excellent performance of low-frequency signal generator circuit
A deaf visual doorbell circuit



Top