chaos in negative resistance

[bhuvanesh]

we know voltage divider bias circuit gives the fraction of the input voltage.i seen in a book that with choosing any one of the resistance has negative ,we achieve amplification.what does that negative resistance mean.how does it affect the circuit.explain me basically

 

[(*steve*)]

Negative resistance is a characteristic of a circuit whereby the current required (or demanded) goes up as the voltage goes down.

A common example is a PC power supply. If your mains voltage dips, the current drawn from the mains increases to maintain the same power to the load. In general this is a characteristic of a switch mode power supply.

You cannot actually buy a negative resistance resistor though Circuits which exhibit this behaviour are generally more complex than a simple 2 terminal device.

Having said that, some semiconductors exhibit negative resistance characteristics over a small range of voltages and/or currents. The classical example is the tunnel diode.

A tunnel diode is a two terminal device that can amplify.

There's plenty of information if you Google for "negative resistance".