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When a signal such as audio is recorded to magnetic tape, this is done with the addition of tape bias: a high frequency AC signal. This bias signal improves the linearity of the magnetization, reducing distortion from the hysteresis of the tape's magnetic particles. Different tape materials work better with different amounts of this bias.
If you are designing an amplifier then you want to bias the output such that it has equal "room" (it's known as voltage swing) for the superimposed AC signal to propagate without clipping. For instance you cannot generate a neative collector voltage with an NPN transistor, so you must bais it with DC and decouple the output with a cap.
That is common in bipolar input opamps since the current direction and magnitude is somewhat known. For example, the LM324 is specified for 100nA input bias current, but only 30nA input offset current. CMOS input opamps often don't have an offset current spec since the bias current is due to leakage and there is no guarantee what its polarity is.
The purpose of the sensor bias circuit (potentiostat) is to maintain the potential of the sensing electrode at a constant level with respect to the reference electrode. This is done by adjusting the voltage of a third ‘counter’ electrode.
Forward-bias is when the anode (the pointy part of the symbol) is positive and the cathode (the bar) is negative. Reverse-bias is when the anode is negative and the cathode is positive. A lot of current flows when the diode is forward-biased, provided that the voltage is higher than 0.6V or so for a silicon diode or 0.3V or so for a germanium ...
2) Input bias current - caused by the finite input resistance of the opamp and results in an "error" voltage drop that depends on the input impedance seen from the opamp terminals. 3) Input offset current - caused by a mismatch between the input bias currents of the individual terminals (not sure what this results in). My questions are the ...
Alternatively, this spec sheet (for this tactical grade IMU) describes its bias repeatability with this footnote: Bias repeatability provides an estimate for long-term drift in the bias, as observed during 500 hours of high temperature operating life at +105C. This seems to estimate the change in bias over a single 500-hour run.
The quiescent point is by definition a state of a circuit in which all the inputs (meaning voltage and current levels, but also component values and environmental conditions) are fixed. It's generally used in circuit analysis to find the operating region of active components, such as transistor and Op-Amps, and then perform a time-based ...
When self bias gain << β Av depends more on R tolerances and Iq. THD is the asymmetry of large signal output and reduces by THD(nfb)~THD(Hbias)*Av/β This done by moving your R2 to Rcb and choosing Rin such that Av is slightly less than Rcb/Rt. \$\endgroup\$
I read this text on op amp input bias current. It says: The input pins are the base pins of the transistor (or gate pins in the case of FET inputs). In order for the input transistor to operate, the base current (IB) must flow. This base current is the input bias current. Often the input bias current is modeled by this kind of model: