22 Facts About Negative resistance

In electronics, negative resistance is a property of some electrical circuits and devices in which an increase in voltage across the device's terminals results in a decrease in electric current through it.

Negative resistance is an uncommon property which occurs in a few nonlinear electronic components.

In general, a negative differential resistance is a two-terminal component which can amplify, converting DC power applied to its terminals to AC output power to amplify an AC signal applied to the same terminals.

Examples of devices with negative differential resistance are tunnel diodes, Gunn diodes, and gas discharge tubes such as neon lamps, and fluorescent lights.

The Negative resistance is the ratio of voltage to current, the inverse slope of the line and is constant.

Resistance can still be defined, but the Negative resistance is not constant; it varies with the voltage or current through the device.

One way in which the different types of Negative resistance can be distinguished is in the directions of current and electric power between a circuit and an electronic component.

Negative differential resistance devices have unique capabilities: they can act as one-port amplifiers, increasing the power of a time-varying signal applied to their port, or excite oscillations in a tuned circuit to make an oscillator.

The physical processes which cause negative resistance are diverse, and each type of device has its own negative resistance characteristics, specified by its current–voltage curve.

In electronics, the term "Negative resistance" is customarily applied only to passive materials and components – such as wires, resistors and diodes.

The negative static resistance of a power source is a rather abstract and not very useful quantity, because it varies with the load.

Examples of circuits with this type of negative resistance are the negative impedance converter, gyrator, Deboo integrator, frequency dependent negative resistance, and generalized immittance converter .

All linear oscillator circuits have negative resistance although in most feedback oscillators the tuned circuit is an integral part of the feedback network, so the circuit does not have negative resistance at all frequencies but only near the oscillation frequency.

Negative differential resistance devices are widely used to make electronic oscillators.

Negative resistance oscillators are mainly used at high frequencies in the microwave range or above, since feedback oscillators function poorly at these frequencies.

At large amplitudes the circuit is nonlinear, so the linear analysis above does not strictly apply and differential Negative resistance is undefined; but the circuit can be understood by considering to be the "average" Negative resistance over the cycle.

Negative differential resistance devices are used in switching circuits in which the device operates nonlinearly, changing abruptly from one state to another, with hysteresis.

The advantage of using a negative resistance device is that a relaxation oscillator, flip-flop or memory cell can be built with a single active device, whereas the standard logic circuit for these functions, the Eccles-Jordan multivibrator, requires two active devices .

The negative resistance here is implied were one to consider the neuron a typical Hodgkin–Huxley style circuit model.

Negative resistance was first recognized during investigations of electric arcs, which were used for lighting during the 19th century.

Negative resistance was one of the first to report negative capacitance and inductance.

Negative resistance used these to build solid-state amplifiers, oscillators, and amplifying and regenerative radio receivers, 25 years before the invention of the transistor.