High Frequency Behaviour of a Resistor AIM AND

High Frequency Behaviour of a Resistor

AIM AND APPARATUS Aim: To obtain the high frequency response of a wire wound resistor Apparatus: MATLAB LAB: - CEII (SEM V EXTC) 2

THEORY • LAB: - CEII (SEM V EXTC) 3

TYPES OF RESISTORS • Carbon Composition • Wire wound • Metal Film • Thin film LAB: - CEII (SEM V EXTC) 4

WIRE WOUND RESISTOR LAB: - CEII (SEM V EXTC) 5

• Lead Inductance L 2 • Inductance of the metal wire L 1 • C 1 capacitance between metal winding turns separated by core • C 2 Capacitance between leads separated by air LAB: - CEII (SEM V EXTC) 6

EQUIVALENT CIRCUIT • L 1 > L 2 • C 1 > C 2 • by neglecting L 2 , C 2 LAB: - CEII (SEM V EXTC) 7

IMPEDANCE AND FREQUENCY RESPONSE At very low f, L is short circuited and C is open circuited and parasitic elements are neglected and circuit reduces to only one resistor so initially impedance is of resistance only. At low f as a parallel resonant circuit low value impedance i. e of inductor is dominating. At high frequencies capacitor impedance dominates. The point where the curve changes its behavior is resonant frequency. LAB: - CEII (SEM V EXTC) 8

CARBON COMPOSITION RESISTOR LAB: - CEII (SEM V EXTC) 9

PROBLEM • LAB: - CEII (SEM V EXTC) 10

REFERENCES • www. physics-and-radio-electronics. com • RF Circuit Design- Theory and Application-Reinhold Ludwig, Pavel Bretchko LAB: - CEII (SEM V EXTC) 11