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Negative resistance (voltage controlled) oscillator: Since VCNR ("N" type) devices require a low impedance bias and are stable for load impedances less than r, [103] the ideal oscillator circuit for this device has the form shown at top right, with a voltage source V bias to bias the device into its negative resistance region, and parallel ...
The negative-resistance oscillator model is not limited to one-port devices like diodes; feedback oscillator circuits with two-port amplifying devices such as transistors and tubes also have negative resistance. [15] [16] [11] [17] At high frequencies, three terminal devices such as transistors and FETs are also used in negative resistance ...
This property, called hysteresis, allows the bulb to function as an oscillator. Hysteresis is due to the bulb's negative resistance, the fall in voltage with increasing current after breakdown, [7] [14] which is a property of all gas-discharge lamps. Up until the 1960s sawtooth oscillators were also built with thyratrons.
The transitron oscillator, invented by Cledo Brunetti in 1939, [12] (although a similar effect was observed in tetrodes by Balthasar van der Pol in 1926, [20] and Edward Herold described a similar oscillator in 1935 [21]) is a negative resistance oscillator circuit using a pentode vacuum tube, in which, instead of the plate, the screen grid has ...
Figure 4: Ideal Colpitts oscillator model (common-collector configuration) One method of oscillator analysis is to determine the input impedance of an input port neglecting any reactive components. If the impedance yields a negative resistance term, oscillation is possible. This method will be used here to determine conditions of oscillation ...
The negative impedance converter (NIC) is an active circuit which injects energy into circuits in contrast to an ordinary load that consumes energy from them.This is achieved by adding or subtracting excessive varying voltage in series to the voltage drop across an equivalent positive impedance.
A "locally active resistor" is a device that has negative resistance and is active (it can amplify), providing the power to generate the oscillating current. The locally active resistor and nonlinearity are combined in the device N R, which is called "Chua's diode". This device is not sold commercially but is implemented in various ways by ...
The negative differential resistance, combined with the timing properties of the intermediate layer, is responsible for the diode's largest use: in electronic oscillators at microwave frequencies and above. A microwave oscillator can be created simply by applying a DC voltage to bias the device into its negative resistance region. In effect ...