Thermometer without power switch

A thermometer comprising:

• a body member;
• a tip member secured to the body member;
• a thermal sensor mounted on the inside of the tip member, adapted for sensing a temperature and producing a temperature signal;
• a set of lead wires, coupled to the thermal sensor for transmission of the temperature signal;
• a display unit, disposed on the body member;
• a processor, disposed to electrically connect the set of lead wires to receive the temperature signal and drive the display unit for display of a corresponding temperature reading;
• a rear cover, secured to the body member;
• and
• a mechanical selector, disposed between the processor and the rear cover, the types of temperature scale displayed in the display unit being selected by pushing the mechanical selector from the rear cover;
• wherein the processor comprises a pin for types of temperature scale conversion and the mechanical selector comprises:
• a hole, formed located on a surface of the rear cover;
• a channel, disposed within the rear cover and communicated with the hole;
• an elastic member comprising a main portion, a first protrusion portion extended from the main portion toward the channel, a second protrusion portion extended from the main portion toward the processor;
• and
• a connection line, disposed to electrically connect the pin for keeping a voltage, wherein the voltage of the pin is changed to convert the types of temperature scale by pushing the first protrusion portion from the hole and the channel within the rear cover such that the second protrusion portion is moved to cut the connection line.