An Impatt diode has
n+ -
p -
i -
p + structure and is used with reverse bias.
It exhibits negative resistance and operates on the principle of avalanche breakdown.
Impatt diode circuits are classified as broadly tunable circuit, low Q circuit and high Q circuit.
The impedance of Impatt diode is a few ohms. The word Impatt stands for Impact Avalanche Transit Time diode.
The features of Impatt diode oscillator are : frequency 1 to 300 GHz, Power output (0.5 W to 5 W for single diode circuit and upto 40 W for combination of several diodes), efficiency about 20%.
Its applications include police radar systems, low power microwave transmitter etc.
