Temperature measuring apparatus

Temperature indicating means comprising, in combination:

• power supply means including ground means and first and second power terminal means;
• constant current transistor means including an emitter resistively connected to said first power terminal means, a base connected through a zener diode to said first power terminal means and a collector;
• temperature sensing diode means connected between said collector and said ground means;
• temperature compensated constant voltage reference means including output means for supplying a constant voltage reference over a wide range of temperatures with respect to said ground means, said constant voltage reference means including,
• constant current second transistor means including an emitter resistively connected to said second power terminal means, a base connected through voltage dropping diode means to said second power terminal means and a collector connected through a series connection of a temperature compensating diode means, and a second zener diode means to said ground means, and
• potentiometer means connected between said collector of said second transistor means and said ground means and having a wiper connected to the output means thereof;
• and
• summing means connected to said temperature sensing diode means and to said output means for providing an output indication of temperature of said sensing diode means as a function of the voltage across said sensing diode means as compared to said reference voltage.