The floating immittance emulator is presented in four embodiments in which four new topologies for emulating floating immittance functions are detailed. Each circuit uses three current-feedback operational-amplifiers (CFOAs) and three passive elements. The present topologies can emulate lossless and lossy floating inductances; capacitance, resistance, and inductance multipliers; and frequency-dependent positive and negative resistances.

The floating immittance emulator is presented in four embodiments in which four new topologies for emulating floating immittance functions are detailed. Each circuit uses three current-feedback operational-amplifiers (CFOAs) and three passive elements. The present topologies can emulate lossless and lossy floating inductances; capacitance, resistance, and inductance multipliers; and frequency-dependent positive and negative resistances.

The floating immittance emulator is presented in four embodiments in which four new topologies for emulating floating immittance functions are detailed. Each circuit uses three current-feedback operational-amplifiers (CFOAs) and three passive elements. The present topologies can emulate lossless and lossy floating inductances; capacitance, resistance, and inductance multipliers; and frequency-dependent positive and negative resistances.

The floating immittance emulator is presented in four embodiments in which four new topologies for emulating floating immittance functions are detailed. Each circuit uses three current-feedback operational-amplifiers (CFOAs) and three passive elements. The present topologies can emulate lossless and lossy floating inductances; capacitance, resistance, and inductance multipliers; and frequency-dependent positive and negative resistances.

The floating immittance emulator is presented in four embodiments in which four new topologies for emulating floating immittance functions are detailed. Each circuit uses three current-feedback operational-amplifiers (CFOAs) and three passive elements. The present topologies can emulate lossless and lossy floating inductances; capacitance, resistance, and inductance multipliers; and frequency-dependent positive and negative resistances.

The floating immittance emulator is presented in four embodiments in which four new topologies for emulating floating immittance functions are detailed. Each circuit uses three current-feedback operational-amplifiers (CFOAs) and three passive elements. The present topologies can emulate lossless and lossy floating inductances; capacitance, resistance, and inductance multipliers; and frequency-dependent positive and negative resistances.

A pseudo resistor circuit and a charge amplifier include a first field effect transistor; a second field effect transistor having electrical characteristics matched with electrical characteristics of the first field effect transistor; and a voltage dividing circuit with terminal of a reference resistor electrically connected to a source terminal of the second field effect transistor. Further, a first operational amplifier with an output terminal is connected to a gate terminal of the first field effect transistor and a gate terminal of the second field effect transistor and in which midpoint voltage of the voltage dividing circuit is input into either an inverting or non-inverting input terminal and reference voltage is input into the other of the inverting and non-inverting input terminal. Furthermore, a second operational amplifier supplies voltage resulting from inversion and amplification of drain voltage of the first field effect transistor into the other terminal of the resistor.

A method and system of providing an active differential resistor. The active differential resistor includes a diode having a first node and a second node. There is a capacitor coupled in series between the first node of the diode and an input of the active differential resistor. There is a current source coupled across the first node and the second node of the diode and configured to forward bias the diode such that a Johnson-Nyquist noise of the active differential resistor is replaced by a shot noise.

A pseudo resistance circuit includes a first gate voltage adjustment circuit that adjusts respective currents of first and second current sources and also adjusts a gate voltage of a second field effect transistor to equalize or substantially equalize a drain voltage of the second field effect transistor and a voltage of a first end portion of a reference resistance element and controls a drain voltage of a first field effect transistor and the drain voltage of the second field effect transistor to maintain a constant or substantially constant relationship with each other; and a second gate voltage adjustment circuit that adjusts a gate voltage of the first field effect transistor to control the gate voltage of the second field effect transistor and the gate voltage of the first field effect transistor to maintain a constant or substantially constant relationship with each other.

A controller for an electronically controlled resistor, comprising a controllable current generator that outputs an output current; an amplifier receiving an input voltage proportional to the output current, and outputting an amplified input voltage to a first input of an adder; a voltage divider connected between a high-potential terminal and a low-potential terminal of the electronically controlled resistor; a buffer stage receiving an output of an external sense resistor, and outputting a buffered voltage to a controllable current generator to control the output current and to a second input of the adder, wherein the adder outputs a summed voltage; and an operational amplifier receiving the divided voltage and the summed voltage and outputting a control voltage to an external active element, wherein the active element and the sense resistor are connected in series between the high-potential terminal and the low-potential terminal of the electronically controlled resistor.