A Thermocouple is a terrific way to measure temperature. The effects of temperature change on dissimilar metals produces a measurable voltage. But to make that measurement you need an amplifier circuit designed for the thermocouple being used. Linear Technology LTC 1049 Low Power Zero-Drift Operational Amplifier with Internal Capacitors While researching “Zero Drift Amplifiers” as

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Tech Note on Op-Amps Driving Capacitance


A great tech not on OP Amps driving capacitance.

Q. How does capacitive loading affect op amp performance?

A. To put it simply, it can turn your amplifier into an oscillator. Here’s how:

Op amps have an inherent output resistance, Ro, which, in conjunction with a capacitive load, forms an additional pole in the amplifier’s transfer function. As the Bode plot shows, at each pole the amplitude slope becomes more negative by 20 dB/ decade. Notice how each pole adds as much as -90° of phase shift. We can view instability from either of two perspectives. Looking at amplitude response on the log plot,circuit instability occurs when the sum of open-loop gain and feedback attenuation is greater than unity. Similarly, looking at phase response, an op amp will tend to oscillate at a frequency where loop phase shift exceeds -180°, if this frequency is below the closed-loop bandwidth. The closed-loop bandwidth of a voltage-feedback op amp circuit is equal to the op amp’s bandwidth product (GBP, or unity-gain frequency), divided by the circuit’s closed loop gain (ACL).

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New Instrumentation Amp

Instrumentation Amp ICON

We used to build amplifiers for digital scales (weighing Instrumentation)  where we would sample a full scale voltage reference and a ground reference and from there digitally cancel out gain and baseline drift.  Nowadays the amplifier itself can do a lot of this correction.  We used to call these amplifiers “coppers” referring to the process

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