Combined temperature compensation and zero-offset control

Claim 2

In an amplifier having an input, an output, and a feedback loop from the output, a temperature compensating and zero setting circuit comprising: a first voltage divider adapted to be connected arross a difference in potential; a diode interposed in the voltage divider circuit and poled in the direction of easy conductivity; a second voltage divider circuit in series with a portion of said voltage divider and in parallel with said diode; adjustable wiper means adapted to couple said second voltage divider circuit to a common potential source; and coupling means connecting the diode to the feedback loop for applying to the feedback loop a signal complementary to the thermal drift of the amplifier for substantially cancelling the effects of thermal drift on the amplifier.

Claim 3

The circuit of claim 1, above, further including a zener diode connected in parallel with said second voltage divider circuit and poled in the direction opposite to that of easy conductivity.

Claim 4

The circuit of claim 1, above, wherein said first voltage divider is selected to have a thermal characteristic with a slope similar to the empirically determined slope of the thermal characteristic of the amplifier.

Claim 5

The circuit of claim 1, above, wherein a positive or negative thermal characteristic is achieved by alternatively connecting said coupling means to the cathode and anode of said diode, respectively.

Claim 6

In an amplifier having an inverting and a noninverting input and an empirically determined thermal characteristic having a first slope, means for compensating for the thermal characteristic comprising: a voltage divider circuit having an upper branch and a lower branch; a diode poled in the direction of easy conductivity coupling said upper and lower branches, said voltage divider providing across said diode, a second thermal characteristic slope; zero setting means including a second voltage divider circuit connected in series with a portion of said voltage divider circuit and in parallel with said diode and adjustable wiper means adjustably connecting said second voltage divider circuit to a common potential source; and connecting means coupling a one of the anode and cathode of said diode to the inverting amplifier input to provide a compensating signal having a slope of proper sign and magnitude, whereby the thermal characteristic of the amplifier is balanced out by a feedback signal from said voltage divider circuit.

Claim 7

In an amplifier having an inverting and a noninverting input and an empirically determined thermal characteristic having a first slope, means for compensating for the thermal characteristic comprising: a voltage divider circuit having an upper branch and a lower branch; a diode poled in the direction of easy conductivity coupling said upper and lower branches, said voltage divider providing across said diode, a second thermal characteristic slope; zero setting means including a second voltage divider circuit connected in series with a portion of said voltage divider circuit and in parallel with said diode and adjustable wiper means adjustably connecting said second voltage divider circuit to a common potential source; and connecting means coupling a one of the anode and cathode of said diode to the inverting amplifier input to provide a compensating signal having a slope of proper sign and magnitude, whereby the thermal characteristic of the amplifier is balanced out by a feedback signal from said voltage divider circuit.

Claim 8

The apparatus of claim 5, above, wherein a positive thermal characteristic is corrected for by coupling the diode cathode anode to the inverting input.

Claim 9

The apparatus of claim 5, above, wherein a negative thermal characteristic is corrected for by coupling the diode anode to the inverting input.