Because a wide range of circuits, including tuned amplifiers, filters, oscillators and many more, depend on circuit component values being accurate, testing inductance is a common occurrence in the electronics lab. There is a variety of inductor meters to choose from, depending on the type and size of inductor to be measured. Small-value inductances of up to perhaps 3 mH are best calibrated using an RF inductance meter, because they require a higher frequency in order to exhibit a sizable reactance.

If you need to characterize the inductance of a component over a range of frequencies, then inductance analyzers provide such capability over typically a 20 Hz to 1 MHz range, though they vary by model. If you want to learn more about available inductance meter types and styles, read on.

1. Learn about digital inductance meters.

2. Understand the advantages of inductance analyzers over standard inductance meters.

3. Switch to RF inductance meters when measuring RF inductors.

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Shop for digital inductance meters

Digital inductance meters are generally small, hand-held units that are designed for the convenience of portability, while being designed with a high degree of accuracy, input overload protection and low power consumption. With the advent of the digital inductance meter, the need for complex LCR meters is eliminated in nearly all cases. It is common to find digital inductance meters covering inductance ranges from 2 mH all the way up to 20 H.

I recommend: Spread Spectrum Scene Online provides an informative review of the AADE Digital Inductance/Capacitance Meter. Circuit Specialists carries the model CSI6243 Digital Capacitance and Inductance meter and describes how the meter is intended only for low frequency inductors and capacitors as the testing frequency is only 900 Hz.

Consider inductance analyzers for characterizing inductance over a frequency range

An inductance analyzer is usually in the form of automated test equipment that can be programmed or can receive instructions via an IEEE-488 or RS-232 interface bus to conduct a sequence of inductance measurements over a range of frequencies. The result is a plot or series of data points of inductance vs. frequency for an inductor or other component being tested. Components other than inductors can also exhibit measurable amounts of inductance.

I recommend: QuadTech provides a description of its model 1910 Inductance analyzer, including answers to why you should buy one, features, a product package description and a list of optional accessories. Wayne Kerr Electronics provides a full summary description of its GPIB-controlled model 3255 series inductance analyzers. The unit works with LabVIEW and is able to print out test results.

Use RF inductance meters for inductors designed for operation over 100 kHz

If you need to measure the inductance of slug-tuned or toroidal-wound inductors that are designed for RF, you should use an RF inductance meter in order to obtain the best accuracy. That's because the core permeability of these types of inductors is optimized for operation at RF frequencies, i.e. 3-to-30 MHz.

I recommend: Monty Northrup gives a full description of his design of an RF inductance meter. The information includes performance calculations and is complete enough to enable hobbyists to build them in their electronics labs. Similarly, Lloyd Butler has a site where he gives a full description of his design for an RF Inductance meter.

Inductance meters come in a number of styles and models, from digital hand helds to bench models to portables. The frequencies of measurement vary. No longer are RF inductance meters used only by radio hams or electrical technicians, but many high-tech and specialized fields measure inductance for the ever-expanding and growing technology needs of our modern world.

Inductor meters measure the phenomena of what engineers, scientists and electrical experts attempt to harness and measure to keep our society and way of life sustained. When choosing the right inductance meter, consider these options:

1. Look for hand held digital inductance meters that you can carry with you.

2. Use bench or portable models in your labs.

3. Find LCR and RCL models for testing inductance.

4. Locate inductance bridges for sophisticated applications.

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Find hand held and digital inductance meters for convenience

Get your inductance meters small and handy for your production, laboratory, service and school needs. Use RF inductance meters with batteries, alligator clips and holsters.

I recommend: Find digital inductance meters small in size and battery operated for temperatures ranging from 64 F to 82 F at ApogeeKits. Look at HMC Electronics hand helds that measure capacitance and inductance to 0.7%. These meters come in various modes and with auto power-off. Optional AC adapters or 9-volt batteries power them.

Purchase inductance analyzers and bench and portable models for long-term use

Inductance analyzers and meters come in different sizes and shapes to meet your specifications and needs as business owner and electrical or lab professional.

I recommend: Purchase a bench model inductance analyzer at Wayne Kerr Electronics. You will find various models with choice of AC drive levels or DC bias currents. Frequencies range from 20 Hz to one MHz. Find LCR portable models at ValueTronics. These are bigger than hand helds, yet smaller and more conveniently styled than a bench. The inductance range is 0.10 uH to 19.99 H. Refurbished models are available with 90-day warranties.

Locate LCR inductor meters for testing inductance

Whether you need LCR, RCL or RF frequency inductance meters, there are numerous options available.

I recommend: At QuadTech, LCR meters test inductance accuracy and frequency. Try TestExtra for LCR meters with test frequencies from 12 Hz to 200 kHz, various accuracy levels, test modes and displays.

Buy an inductance bridge for sophisticated measurements

Sometimes you need an inductance bridge for fine-tuned precision work.

I recommend: Look at the sophisticated models of inductance bridges at LBA Group that use modern equipment for RF engineering, testing of radar systems and vector impedance. Hotek Technologies offers inductance bridge LCR inductance meters with a number of options for high accuracy.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  An inductance meter is useful for a wide variety of applications and fields from medical, to space, to the switches and circuitry in residential homes. Good inductance meters are easy to find, but remember that in our competitive market, you can be particular and find meters to meet your specific fine-tuned needs.

Inductance analyzers, also called LC or LCR meters, vary in costs based on reading accuracy and resistance in measurement. An inductance meter could cost around $10 or might cost close to $10,000, depending on the complexity of the instrument and other variables it measures.

When considering the pricing for inductor meters, determine whether you want to work with analog or digital or whether you would be better off with a multimeter, which also measures other variables. When considering pricing and costs you might want to consider the following options:

1. Save costs on RF inductance meters by making your own with spare parts or by using kits.

2. Reduce inductance meter pricing and costs by considering the purchase of an analog inductance meter.

3. Compare prices on digital inductance meters to ensure the highest accuracy in readout.

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Make your own inductance meter to save on inductance meter prices

When you use spare parts lying around your workspace or purchase a kit so you can make your own, you save on the costs for RF inductance meters since you can make one for a few dollars to a little over $50, depending on the intricacy of your kit. This also gives you the opportunity to build your capacitor-inductance meter to your own unique specifications.

I recommend: Lloyd Butler VK5BR offers detailed instructions for making your own inductance meter from parts lying around your work area. Electronics-DIY.com offers kits to consumers who want a basis for making their inductance meter. The kit runs around $50 and includes detailed instructions and all parts necessary.

Use analog RF inductance meters for simplicity in measurement

If you want an inductance meter, but aren't concerned about exact readouts, look into analog inductance meter pricing and costs. The analog meter generally uses a needle on a calibrated scale to display values and works best with lower resistance.

I recommend: Tektronix describes the difference between analog inductor meters, digital inductance meters and multimeters. It recommends places to purchase your inductor meter, commenting on products quality and prices, which range up to approximately $100 for an inductor. EquipTek provides a list of various analog inductance meters and offers pictures for some of them. Its prices range from approximately $65 to over $500.

Consider purchasing digital inductor meters for greater accuracy in readings

Digital inductor meters range from about $50 to about $150, and many professionals prefer them to their analog counterparts due to increased accuracy.

I recommend: The Armory offers instructions for making an adapter that measures inductance on a digital multimeter. It boasts that you can make this inductor meter for a few dollars. Global Test Supply offers a selection of digital inductor meters ranging in price from a $200 to $10,000.