Schering Bridge...The Schering bridge, one of the most important ac bridges is used extensively for the measurement of Capacitors. The basic circuit arrangement is shown in the schematic

OutlineIntroduction to AC Bridges

Maxwell’s BridgeHay Bridge

Schering BridgeWein Bridge

Sajan P. PhilipAP/ECE/BIT

June 16, 2013

Sajan P. Philip AP/ECE/BIT AC Bridges

Schering Bridge

Schering Bridge by Sajan P. Philip, is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License. You are free to use, distribute and modify it, including for commercial purposes, provided you acknowledge the source and share-alike.To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/4.0/




Introduction to Schering BridgeBalance Equation of Schering Bridge

Schematic Diagram of Schering Bridge 20






Introduction to Schering Bridge 21

The Schering bridge, one of the most important ac bridges is used extensivelyfor the measurement of Capacitors.

The basic circuit arrangement is shown in the schematic.Arm 1 contains a parallel combination of a resistor and a capacitor.The standard arm contains only a capacitor.The standard capacitor is usually a high quality mica capacitor for generalmeasurement.The standard capacitor is usually an air capacitor for insulation measurement.A good quality mica capacitor has a very low resistance losses and therefore a phase angle of approx. 90degrees.An air capacitor when designed carefully has a very stable value and a very small electric field.

Hence insulating material to be tested can easily be kept out of any strong fields.







The Schering bridge, one of the most important ac bridges is used extensivelyfor the measurement of Capacitors.The basic circuit arrangement is shown in the schematic.

Arm 1 contains a parallel combination of a resistor and a capacitor.The standard arm contains only a capacitor.The standard capacitor is usually a high quality mica capacitor for generalmeasurement.The standard capacitor is usually an air capacitor for insulation measurement.A good quality mica capacitor has a very low resistance losses and therefore a phase angle of approx. 90degrees.An air capacitor when designed carefully has a very stable value and a very small electric field.








The Schering bridge, one of the most important ac bridges is used extensivelyfor the measurement of Capacitors.The basic circuit arrangement is shown in the schematic.Arm 1 contains a parallel combination of a resistor and a capacitor.

The standard arm contains only a capacitor.The standard capacitor is usually a high quality mica capacitor for generalmeasurement.The standard capacitor is usually an air capacitor for insulation measurement.A good quality mica capacitor has a very low resistance losses and therefore a phase angle of approx. 90degrees.An air capacitor when designed carefully has a very stable value and a very small electric field.








The Schering bridge, one of the most important ac bridges is used extensivelyfor the measurement of Capacitors.The basic circuit arrangement is shown in the schematic.Arm 1 contains a parallel combination of a resistor and a capacitor.The standard arm contains only a capacitor.

The standard capacitor is usually a high quality mica capacitor for generalmeasurement.The standard capacitor is usually an air capacitor for insulation measurement.A good quality mica capacitor has a very low resistance losses and therefore a phase angle of approx. 90degrees.An air capacitor when designed carefully has a very stable value and a very small electric field.








The Schering bridge, one of the most important ac bridges is used extensivelyfor the measurement of Capacitors.The basic circuit arrangement is shown in the schematic.Arm 1 contains a parallel combination of a resistor and a capacitor.The standard arm contains only a capacitor.The standard capacitor is usually a high quality mica capacitor for generalmeasurement.

The standard capacitor is usually an air capacitor for insulation measurement.A good quality mica capacitor has a very low resistance losses and therefore a phase angle of approx. 90degrees.An air capacitor when designed carefully has a very stable value and a very small electric field.








The Schering bridge, one of the most important ac bridges is used extensivelyfor the measurement of Capacitors.The basic circuit arrangement is shown in the schematic.Arm 1 contains a parallel combination of a resistor and a capacitor.The standard arm contains only a capacitor.The standard capacitor is usually a high quality mica capacitor for generalmeasurement.The standard capacitor is usually an air capacitor for insulation measurement.

A good quality mica capacitor has a very low resistance losses and therefore a phase angle of approx. 90degrees.An air capacitor when designed carefully has a very stable value and a very small electric field.








The Schering bridge, one of the most important ac bridges is used extensivelyfor the measurement of Capacitors.The basic circuit arrangement is shown in the schematic.Arm 1 contains a parallel combination of a resistor and a capacitor.The standard arm contains only a capacitor.The standard capacitor is usually a high quality mica capacitor for generalmeasurement.The standard capacitor is usually an air capacitor for insulation measurement.A good quality mica capacitor has a very low resistance losses and therefore a phase angle of approx. 90degrees.

An air capacitor when designed carefully has a very stable value and a very small electric field.








The Schering bridge, one of the most important ac bridges is used extensivelyfor the measurement of Capacitors.The basic circuit arrangement is shown in the schematic.Arm 1 contains a parallel combination of a resistor and a capacitor.The standard arm contains only a capacitor.The standard capacitor is usually a high quality mica capacitor for generalmeasurement.The standard capacitor is usually an air capacitor for insulation measurement.A good quality mica capacitor has a very low resistance losses and therefore a phase angle of approx. 90degrees.An air capacitor when designed carefully has a very stable value and a very small electric field.























Balance Equation of Schering Bridge 22

The Balance conditions require that the sum of the phase angles of arms 1 and4 equals the sum of the phase angles of arms2 and 3.

Since the standard capacitor is in arm 3, the sum of the phase angles of arms 2and 3 will be 0+90=90 degrees.However in the case of arm 1 and 4, the unknown will have a phase anglesmaller than 90 degrees.Hence it is necessary to give arm 1 a small capacitive angle by connecting acapacitor C1 in parallel with Resistor R1.The balance equation is;Zx=Z2Z3Y1

Rx − jωCx

=R2

(−jωC3

)(1R1

+ jωC1

)







The Balance conditions require that the sum of the phase angles of arms 1 and4 equals the sum of the phase angles of arms2 and 3.Since the standard capacitor is in arm 3, the sum of the phase angles of arms 2and 3 will be 0+90=90 degrees.

However in the case of arm 1 and 4, the unknown will have a phase anglesmaller than 90 degrees.Hence it is necessary to give arm 1 a small capacitive angle by connecting acapacitor C1 in parallel with Resistor R1.The balance equation is;Zx=Z2Z3Y1

Rx − jωCx

=R2

(−jωC3

)(1R1

+ jωC1

)







The Balance conditions require that the sum of the phase angles of arms 1 and4 equals the sum of the phase angles of arms2 and 3.Since the standard capacitor is in arm 3, the sum of the phase angles of arms 2and 3 will be 0+90=90 degrees.However in the case of arm 1 and 4, the unknown will have a phase anglesmaller than 90 degrees.

Hence it is necessary to give arm 1 a small capacitive angle by connecting acapacitor C1 in parallel with Resistor R1.The balance equation is;Zx=Z2Z3Y1

Rx − jωCx

=R2

(−jωC3

)(1R1

+ jωC1

)







The Balance conditions require that the sum of the phase angles of arms 1 and4 equals the sum of the phase angles of arms2 and 3.Since the standard capacitor is in arm 3, the sum of the phase angles of arms 2and 3 will be 0+90=90 degrees.However in the case of arm 1 and 4, the unknown will have a phase anglesmaller than 90 degrees.Hence it is necessary to give arm 1 a small capacitive angle by connecting acapacitor C1 in parallel with Resistor R1.

The balance equation is;Zx=Z2Z3Y1

Rx − jωCx

=R2

(−jωC3

)(1R1

+ jωC1

)







The Balance conditions require that the sum of the phase angles of arms 1 and4 equals the sum of the phase angles of arms2 and 3.Since the standard capacitor is in arm 3, the sum of the phase angles of arms 2and 3 will be 0+90=90 degrees.However in the case of arm 1 and 4, the unknown will have a phase anglesmaller than 90 degrees.Hence it is necessary to give arm 1 a small capacitive angle by connecting acapacitor C1 in parallel with Resistor R1.The balance equation is;

Zx=Z2Z3Y1

Rx − jωCx

=R2

(−jωC3

)(1R1

+ jωC1

)







The Balance conditions require that the sum of the phase angles of arms 1 and4 equals the sum of the phase angles of arms2 and 3.Since the standard capacitor is in arm 3, the sum of the phase angles of arms 2and 3 will be 0+90=90 degrees.However in the case of arm 1 and 4, the unknown will have a phase anglesmaller than 90 degrees.Hence it is necessary to give arm 1 a small capacitive angle by connecting acapacitor C1 in parallel with Resistor R1.The balance equation is;Zx=Z2Z3Y1

Rx − jωCx

=R2

(−jωC3

)(1R1

+ jωC1

)








Rx − jωCx

=R2

(−jωC3

)(1R1

+ jωC1

)Sajan P. Philip AP/ECE/BIT AC Bridges







Rx − jωCx

=R2

(−jωC3

)(1R1

+ jωC1

)Sajan P. Philip AP/ECE/BIT AC Bridges






Rx − jωCx

=R2C1C3− jR2ωC3R1

Equating the real and imaginary terms, we find that

Rx=R2C1C3

Cx=C3R1R2







Rx − jωCx



Rx=R2C1C3

Cx=C3R1R2







Rx − jωCx



Rx=R2C1C3

Cx=C3R1R2







Rx − jωCx



Rx=R2C1C3

Cx=C3R1R2







Rx − jωCx



Rx=R2C1C3

Cx=C3R1R2


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Schering Bridge...The Schering bridge, one of the most important ac bridges is used extensively for the measurement of Capacitors. The basic circuit arrangement is shown in the schematic