Negative resistance

About: Negative resistance is a research topic. Over the lifetime, 2335 publications have been published within this topic receiving 22341 citations.

Characteristics of the space-charge-limited dielectric diode at very high frequencies

Abstract: The incremental admittance of the space-charge-limited dielectric diode is calculated; it is shown that for all frequencies this can be represented as a conductance and susceptance in parallel. At very high frequencies, transit time effects reduce the forward conductance to 0·667 of the low frequency value and increase the input capacitance to 1·33 of the low frequency value. At low frequencies such that transit time effects can be neglected the reverse biased capacitance is constant and equal to the geometrical electrode capacitance; the forward biased capacitance is constant and equal to 0·75 of the reverse biased capacitance. There are no negative resistance effects at any frequency. Experimental measurements have been made on space-charge-limited cadmium sulphide diodes over the frequency range 50–1000 Mc/s. These confirm the theoretical analysis and support the physical model used for description of space-charge-limited current in solids.

Inverter circuit for discharge lamps for multi-lamp lighting and surface light source system

Abstract: An inverter circuit for discharge lamps for multi-lamp lighting in which the value of a negative resistance characteristic of a fluorescent lamp is controlled, and an excessively set reactance is eliminated by causing a shunt transformer to have a reactance exceeding the negative resistance characteristic. Two coils connected to a secondary winding of a step-up transformer of the inverter circuit are arranged and magnetically coupled to each other to form a shunt transformer for shunting current such that magnetic fluxes generated thereby cancel each other out. Discharge lamps are connected to the coils, respectively, with currents flowing therethrough being balanced. Each discharge lamp is lighted because a reactance of an inductance related to the balancing operation which is in an operating frequency of the inverter circuit, exceeds a negative resistance of the discharge lamps.

Power and stability limitations of resonant tunneling diodes

Abstract: Stability criteria for resonant tunneling diodes are investigated. Details of how extrinsic elements, such as series inductance and parallel capacitance, affect the stability are presented. A GaAs/AlAs/InGaAs/AlAs/GaAs double-barrier diode is investigated, showing the effect of different modes of low-frequency oscillation and the extrinsic circuit required for stabilization. The effect of device stabilization on high-frequency power generation is described. The main conclusions of the paper are: (1) stable resonant tunneling diode operation is difficult to obtain, and (2) the circuit and device conditions required for stable operation greatly reduce the amount of power that can be produced by these devices. >

The Packaged and Mounted Diode as a Microwave Circuit

Abstract: Suitable definitions of the elements in the equivalent circuit of a packaged diode yield a lumped-element circuit with an impedance at its terminals which is the same as the total radial-line impedance of the packaged diode with the outer surface of the diode taken as the terminal surface. Consideration of the packaged diode as a radial-line structure permits an analytical justification for the incorporation of the diode circuit with the circuits of waveguide, coaxial-line, and strip-line diode mounts. As a result, the lumped-element equivalent circuit of a packaged diode can be directly related to the microwave equivalent circuit of the diode and the mount together. Diode element values, which were obtained from low-frequency measurements, have been used in conjunction with the theoretically determined circuits of mounted diodes to predict resonant frequencies at X-band of waveguide, coaxial-line, and stripline mounts holding packaged diodes. Similarly, antiresonant frequencies of greater than 20 Gc/s have been predicted for diodes in a radial cavity. The validity of all these predictions has been verified by measurement.

Two-dimensional numerical analysis of stability criteria of GaAs FET's

Abstract: Stability criteria of GaAs junction-gate FET's are studied by two-dimensional numerical analysis. The analysis covers the wide range of device geometry from the state of the art FET to the so-called Gunn effect digital devices. It is found that a GaAs FET exhibits either of the following three types of characteristics depending upon device geometry and doping concentration. First, for a thin channel with high doping concentration, the device tends to behave as a normal junction-gate FET with saturating current-voltage characteristics. This is even true when the n-l (device length) and n.d (device thickness) products exceed the previously accepted criteria for Gunn oscillation. Second, a stable negative resistance (SNR) is observed in devices with a moderate channel thickness. Third, for a thick channel, the device exhibits a Gunn oscillation with the domain propagating from the gate edge to the drain. These three categories of behavior are mapped on the nd plane with the help of simple analytic considerations. The map is found to compare well with experimental results.