Temperature compensating circuit for use with crystal oscillators and the like

Claim 2

An improved temperature compensating circuit for use with crystal oscillators and the like comprising: a. first and second voltage source terminals; b. a control circuit connected between said first and second source terminals, said control circuit comprising: 1. a thermistor connected between said first source terminal and a first junction; 2.

Claim 3

a resistor connected between said first junction and said second source terminal; 3. a resistor connected between said first source terminal and a second junction; 4. a semiconductor device having current electrodes connected between said second junction and a third junction, and having a control electrode; 5. a resistor connected between said third junction and said second source terminal; 6. a direct current path of selected impedance connected between said first junction and said control electrode; 7. a resistor connected between said first source terminal and said third junction; c. and means for deriving an output from said second junction and one of said source terminals; d. said thermistor being selected to cause saturation of said semiconductor device at a predetermined temperature and control the output at said second junction as the temperature increases above said predetermined

Claim 4

a resistor connected between said first junction and said second source terminal; 3. a resistor connected between said first source terminal and a second junction; 4. a semiconductor device having current electrodes connected between said second junction and a third junction, and having a control electrode; 5. a resistor connected between said third junction and said second source terminal; 6. a direct current path of selected impedance connected between said first junction and said control electrode; 7. a resistor connected between said first source terminal and said third junction; c. and means for deriving an output from said second junction and one of said source terminals; d. said thermistor being selected to cause saturation of said semiconductor device at a predetermined temperature and control the output at said second junction as the temperature increases above said predetermined

Claim 5

temperature. 2. The improved circuit of claim 1 wherein said semiconductor device is an NPN transistor having its collector connected to said second junction and its emitter connected to said third junction.

Claim 6

The improved circuit of claim 1 wherein said semiconductor device is a PNP transistor having its collector connected to said second junction and its emitter connected to said third junction.

Claim 7

The improved circuit of claim 1 or claim 2 or claim 3 and comprising an additional control circuit connected between said second junction and said second source terminal, said additional control circuit comprising a thermistor and at least one resistor connected in series.

Claim 8

A temperature compensating circuit comprising: a. first and second terminals for connection to positive and negative direct current voltages respectively; b. a first thermistor and a first resistor connected in series in that order between said first and second terminals; c. a second resistor, the collector-emitter path of an NPN transistor, and a third resistor connected in series in that order between said first and second terminals; d. a fourth resistor of selected impedance connected between the base of said transistor and the junction of said first thermistor and first resistor; e. a fifth resistor connected between said first terminal and said emitter of said transistor; f. said thermistor decreasing in magnitude as its temperature increases above a pre-determined temperature level to saturate said transistor and raise said collector voltage as said base voltage is raised; g. and means for deriving a compensating output voltage from said collector of said transistor.

Claim 9

A temperature compensating circuit comprising: a. first and second terminals for connection to positive and negative direct current voltages respectively; b. a first thermistor and a first resistor connected in series in that order between said first and second terminals; c. a second resistor, the collector-emitter path of an NPN transistor, and a third resistor connected in series in that order between said first and second terminals; d. a fourth resistor of selected impedance connected between the base of said transistor and the junction of said first thermistor and first resistor; e. a fifth resistor connected between said first terminal and said emitter of said transistor; f. said thermistor decreasing in magnitude as its temperature increases above a pre-determined temperature level to saturate said transistor and raise said collector voltage as said base voltage is raised; g. and means for deriving a compensating output voltage from said collector of said transistor.

Claim 10

The temperature compensating circuit of claim 5 wherein said means for deriving comprises an additional series circuit comprising a sixth resistor, a second thermistor, and a seventh resistor connected in series between said collector of said transistor and said second terminal, and wherein said output voltage is derived from said additional series circuit.

Claim 11

A temperature compensating circuit comprising: a. first and second terminals for connection to positive and negative direct current voltages respectively; b. a first resistor and a first thermistor connected in series in that order between said first and second terminals; c. a second resistor, the emitter-collector path of a PNP transistor, and a third resistor connected in series in that order between said first and second terminals; d. a fourth resistor of selected impedance connected between the base of said transistor and the junction of said first resistor and first thermistor; e. a fifth resistor connected between said second terminal and said emitter of said transistor; f. said thermistor decreasing in magnitude as its temperature increases above a pre-determined temperature level to saturate said transistor and lower said collector voltage as said base voltage is lowered; g. and means for deriving a compensating output voltage from said collector of said transistor.

Claim 12

A temperature compensating circuit comprising: a. first and second terminals for connection to positive and negative direct current voltages respectively; b. a first resistor and a first thermistor connected in series in that order between said first and second terminals; c. a second resistor, the emitter-collector path of a PNP transistor, and a third resistor connected in series in that order between said first and second terminals; d. a fourth resistor of selected impedance connected between the base of said transistor and the junction of said first resistor and first thermistor; e. a fifth resistor connected between said second terminal and said emitter of said transistor; f. said thermistor decreasing in magnitude as its temperature increases above a pre-determined temperature level to saturate said transistor and lower said collector voltage as said base voltage is lowered; g. and means for deriving a compensating output voltage from said collector of said transistor.

Claim 13

The temperature compensating circuit of claim 7 wherein said means for deriving comprises an additional series circuit comprising a sixth resistor, a second thermistor, and a seventh resistor connected in series between said collector of said transistor and said first terminal, and wherein said output voltage is derived from said additional series circuit.