Feature : w1209 thermostat module has a temperature sensor, keys, LED display, relay and requires DC 12v power supply, good quality thermostat controller. Thermostats are devices that sense the temperature of a system so that the temperature is maintained at the desired set point or near to it. Ntc temperature sensor allows the module to intelligently control varied electrical devices based on the temperature. Ntc thermistor has a negative temperature coefficient, which means the resistance decreases with increasing temperature. W1209 has an inbuilt embedded micro-controller, thus not much programming knowledge is required. The module consists of three switches to configure the various parameters including on and off trigger temperatures. The relay can operate at voltages up to a maximum of 240v AC or 14v DC to power on. The temperature is displayed in degree centigrade and with the help of 7-segment display and the relay, the state is displayed with the help of the LED present on the w1209 module.