Measuring Small Inductances with Butterworth's Method

When measuring electrical quantities like inductance, the method used often depends on the specific value range. Measuring small inductances presents unique challenges because the effects of associated resistance, stray capacitance, and measurement frequency become more significant.

Several methods exist for inductance measurement, many of which involve using AC bridges. AC bridges balance impedances to determine the unknown value. For measuring small inductances accurately, especially those found in coils operating at higher frequencies, a method that minimizes interference from resistance and stray elements is crucial.

Let's consider the methods mentioned:

• Kuriyama method: This method is not widely recognized in standard electrical measurement literature for small inductance measurement.
• Butterworths method: Butterworth's bridge is a type of AC bridge circuit specifically designed for measuring self-inductance, particularly suitable for inductances with low quality factors (Q values) or small inductance values, often used at radio frequencies. It helps in accurately determining the inductance value while accounting for the series resistance.
• Felicis method: This method is not commonly cited as a standard technique for inductance measurement.
• Campbells method: Campbell's bridge is another type of AC bridge used for comparing inductances, but Butterworth's bridge is often highlighted for its suitability in measuring small inductances or inductors with significant resistance.

Based on standard electrical measurement principles, Butterworths method is especially suitable for the measurement of small inductances. Its circuit configuration is designed to provide accurate measurements in scenarios where inductance values are small and potentially accompanied by notable series resistance, which is common for small coils or inductors operating at higher frequencies.

Therefore, for measuring small inductances effectively, Butterworth's method is the appropriate choice among the given options.