Temperature Indicator


Temperature Indicator Schematic

Parts List:R1 = 10KIC1 = CA3240ER2 = ThermistorLed1,2,3,4 = Led’s of your choice R3-R7 = 5K BZ1 = Buzzer, 6VR8-R11 = 220 ohm B1 = battery, 9VThis circuit sets off a buzzer after the last Led (led4) is lit.It is a simple but fun circuit to experiment with.You can replace the buzzer with something else, add a trimpot to adjust sensitivity, etc, etc. The possibilities are endles.The CD3240E IC may in some cases be difficult to obtain.Try the following resources below:Digikey order #CA3240EZ-ND$2.04Newark order #CA3240E$2.80Have fun building or bread-boarding this circuit and don’t hesitate to experiment on it!


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