Negative differential resistance describes a region on a component's current-voltage curve where Ohm's law appears to reverse. Instead of drawing more current at higher voltages, the device chokes the flow. Engineers use this unstable region deliberately in oscillator circuits to sustain continuous wave generation.
Heard on the job
We need a component with a steep NDR curve to get this oscillator starting reliably at cold temperatures.
Do not mix it up with
- NDC: NDR and NDC describe the exact same physical phenomenon, just expressed as resistance versus conductance.
Related terms
NDC
A circuit property where an increase in voltage leads to a decrease in current.
Diode
A two-terminal semiconductor component that restricts electrical current to flow in only one direction.
Gunn effect
A phenomenon where a direct current applied to a semiconductor creates high-frequency microwave oscillations.