Heat Indicator Circuit For Water

Tuesday, October 9th, 2018 - Sensor/Detection Circuit

The heat indicator circuit serves to provide a signal or indicator on the water heater with an LED flame that interpret the hot water temperature values. Sensors are used to detect the level of hot water using 4 pieces of NTC to get a 4 point temperature level of the temperature of the heated water. The heat indicator circuit is quite simple and can be seen in the following series of images.

Heat Indicator Circuit For Water

Heat Indicator Circuit For Water

This hot set of indicators can be applied to heating water for showers or to provide hot water radiator indicators on the machine. Hot water sets of indicators can provide a signal indicative of hot water in 4 levels indicated by LED flame. 4 level hot water temperature is obtained by detecting the temperature of the water using 4 pieces of NTC and 4 comparators. The water temperature is read by the NTC sensor is converted as a change in resistance is then used to get a change of voltage using a voltage divider circuit and the NTC resistor. The value of the voltage changes compared with the reference voltage by a voltage comparator constructed from an operational amplifier (op-amp) IC LM324. If the voltage level detection results temperature is higher than the reference voltage, the comparator output voltage will change and turn on the LED connected. The process of getting 4 temperature levels is obtained by adjusting the ratio of the value of the NTC and resistor voltage divider is different for each sensor NTC uses 4 different pieces potentiometer (P1, P2, P3 and P4) for each NTC.

Operating Voltage Of Heat Indicator Circuit

The heat indicator circuit can be operated using a voltage of +9 volts from a 9 volt battery so that more and flexible in its placement.

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