CONDITION RESPONSIVE SIGNAL PRODUCING DEVICE

• US 3,800,300 A
• Filed: 12/23/1971
• Issued: 03/26/1974
• Est. Priority Date: 12/23/1971
• Status: Expired due to Term

• Current Assignee: Ball Brothers Service Corporation
• Original Assignee: Ball Brothers Service Corporation
• Inventors: Van Oosterhout, Jack T.
• Primary Examiner(s): Habecker, Thomas B.
• Application Number:
  US05/211,215
• Time in Patent Office: 824 Days
• Field of Search: 73/362AR 328/3.59 340/228,177VA,27R 331/65 307/271
• US Class Current: 340/870.17
• CPC Class Codes: G01K 1/024 for remote indication
• CPC Class Codes: G01K 7/203 in an oscillator circuit
• CPC Class Codes: G08C 19/26 by varying pulse repetition frequency

Abstract

A circuit device for producing a signal indicative of a particular condition such as, for example, temperature, and for transmitting the signal to a remote location is disclosed herein and includes a circuit arrangement for producing an oscillatory output signal having a frequency indicative of the particular condition. This output signal, in addition to being transmitted, is fed back to the circuit arrangement for eliminating changes in its frequency which would otherwise be caused by fluctuations in the voltage supplies required for operating the circuit device.

Claims

1. A device for producing an output signal indicative of a temperature, said device comprising:

an operational amplifier having a temperature sensing means connected in its negative feedback circuit;

a comparator circuit having a first and second input;

an integrating circuit connected between said operational amplifier and said first input of said comparator circuit;

switching means connected to the output of said comparator circuit for producing an output indicative of said temperature, said output indicative of said temperature being resistively connected to the input of said operational amplifier and the second input of said comparator circuit.

2. A device set forth in claim 1 wherein said switching means comprises:

first and second semiconductor devices;

first and second zener diodes;

first and second junctions adapted for connection with a voltage supplies;

said first zener diode and said first semiconductor being connected in series between the output of said switching means and the output of said comparator and in parallel with the series connection of said second zener and said second semiconductor;

said output of said comparator being connected to said zener diodes;

said first junction being connected to a point between said first zener and said first semiconductor, said second junction being connected to a point between said second zener and said second semiconductor device.

3. A device as set forth in claim 2 wherein each said first and second semiconductor device has an emitter, a collector and a base electrode, said emitter of said first semiconductor being connected to said first junction and said emitter of said second semiconductor being connected to said second junction, said collector of said first semiconductor being connected to said collector of said second semiconductor and to said output of said switching means;

and wherein said base of said first semiconductor is connected to the cathode of said first zener diode and said base of said second semiconductor is connected to the anode of said second zener diode.

4. A device setforth in claim 3 to further comprise a first resistor connected in the input circuit of said operational amplifier;

a second resistor connected in the input circuit of said integrating circuit and a capacitor connected between the input and the output of said integrating circuit;

said operational amplifier having a negative gain equal to the resistance of said temperature sensing means divided by the resistance of said first resistor, said integrating amplifier having a negative gain equal to the capacitance of said capacitor divided by the resistance of said second resistor.