Thermistor unit

The invention discloses a thermistor unit comprising a thermistor, a solid-state relay, a circuit board, a metal wiring column a, a metal wiring column b, a switch and a power supply. The thermistor, the solid-state relay, the metal wiring column a, the metal wiring column b, the switch and the power supply are fixedly arranged on the circuit board; the metal wiring column a is electrically connected with one end of the thermistor; the other end of the thermistor is electrically connected with the third pin of the solid-state relay; the fourth pin of the solid-state relay is electrically connected with the metal wiring column b; the metal wiring column a and the metal wiring column b are externally connected with a control circuit; the first pin and the second pin of the solid-state relay are externally connected with the power supply and the switch respectively; when the thermistor needs to be used to control the circuit automatically, only the first pin and second pin of the solid-state relay are connected with the power supply, so that the first pin and second pin of the solid-state relay are conducted, and the third pin and fourth pin of the solid-state relay enable the connected circuit to be conducted; and otherwise, if the switch is disconnected, the thermistor does not work.