Temperature Meter

Various temperature based project is already published in www.electronicsproject.org. Now here is very simple project “Temperature Meter” build from very few components and can be understand even by beginners. The project temperature meter indicate three stages of temperature i.e. hot, warm and cold.

Circuit description

The entire circuit of temperature meter is build around window discriminator IC TCA965 followed by thermistor and few another components. Thermistor is a special type of resistor whose resistance varies according to change in temperature. Thermistor TH1 is used here as temperature sensor. Resistor R1 with thermistor TH1 is used as potential divider and the value of resistor R1 is so chosen that voltage at junction is half. Variable resistor VR1 with VR2 is used to control the level of temperature indicated by LEDs. The three different LEDs is connected to the output pin 14, 13 and 2 through resistor R3, R4 and R5 respectively in order to indicate the status of temperature. LED1, LED2, LED3 indicate hot, warm, and cold respectively.

temperature meter

PARTS LIST

Resistors (all ¼-watt, ± 5% Carbon)

R1 = 47 KΩ

R2 = 100 KΩ

R3 ,R4, R5 = 4.7 KΩ

VR1, VR2 = 10 KΩ (linear pot.)

Capacitors

C1 = 10 µF/16V (electrolytic)

Semiconductors

IC1 = TCA965

LED1 = Red

LED2 = Yellow

LED3 = Green

Miscellaneous

SW1 = On/Off Switch

Have You Say!

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Comments

  1. I didnt find the value of R4 can you please give it?

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