6.1 INTRODUCTION

AC BRIDGE

FUNCTION

AC bridge are used to measured inductance and capacitance

DESIGN

based on Wheatstone Bridge

FEATURE

consists of four impendance, an ac voltage and detector

DETECTOR

detector can be pair of headphone, lissajous figure and electronic galvanometer

BALANCE

when bridge is balance Z1/Z3 = Z2/Z4

1. MAXWELL'S BRIDGE

measure unknown inductance for low Q factor coils (Q:1-10)

2. HAY'S BRIDGE

measure unknown inductance for high Q factor coils (Q>10)

3. SCHERING'S BRIDGE

measure small capasitors with low voltage

4. WIEN'S BRIDGE

-measure frequency

- measure capacitance