Application Notes

Electrical Safety

AN603: Understanding the CAT Ratings on a Voltmeter

A voltmeter is a widely used instrument in the electrical industry, utilized to measure voltages at various circuit points mainly in order to troubleshoot a problem. As the modern industry continues its quest to keep electricians safe, new standards and test instruments designed with safety and convenience in mind continue to help make that possible.

Ratio Standards

AN104: TEGAM Ratio Transformer Helps Predict Earthquakes

Interesting note about the earthquake prediction, The Earthscope Project and the role of a TEGAM ratio transformer.

AN501: Testing Resolvers Using a Precision Ratio Transformer

A high precision ratio transformer can provide the accuracy and resolution needed for testing resolvers at small angular increments. This document discusses how a precision ratio transformer can be used as a standard for synchro resolvers

RF & Microwave

AN208: Microwave Receiver Linearity Verification

The linearity of an RF or microwave receiver is typically measured at its intermediate frequency. Nonlinearities at high signal levels due to mixer compression, and at low levels due to noise, are then specified as maximum error figures. This application note shows how linearity can be measured over a frequency range of 100kHz to 40GHz using a precision power meter and RF power standards.

AN212: Constructing a 100mW RF Power Reference

Conventional calibrations typically take place in the 1mW to 10mW range. This range can be extended downwards for highly sensitive diode sensors by means of a calibrated attenuator. Raising the calibration level above 10mW is more of a challenge. This application note describes a basic technique for generating an accurate 100 mW power source.

AN213: Return Loss and VSWR Measurement Methods

Both VSWR and Return Loss are a measure of the divergence of a microwave device from a perfect impedance match. They are mathematically interchangeable and result from scalar measurements. This app note describes the use of a TEGAM System IIA Power Sensor Calibration System for VSWR and Return Loss measurements.

AN215: Using Agilent Temperature Compensated Thermistor Mounts With TEGAM Type IV Power Meters

There are many different types of temperature compensated thermistor mounts such as the Agilent 478A and 8478A. Type IV power meters such as Tegam’ s 1806A, 1804, and 1806 can be used to monitor these thermistor mounts.

AN216: Limitations of AM Leveling Loops

Characterizing RF power sensors is commonly done using a direct comparison system which employs a resistive RF power splitter with a power standard connected to a power meter. The microwave source is often maintained at a stable level with an external AM input. This application note discusses the limitations to this technique and some alternatives.

AN217: Measuring Temperature Compensating Thermistors with the TEGAM Model 1830A RF Power Meter

This document explains the theory behind measuring power with a dual bridge Power Meter such as the Agilent 432A and shows the reader how to simplify the measurement with the TEGAM 1830A RF Power Meter.

AN218: Calculating a Calibration Factor

Technicians and engineers use calibration factors when making measurements; but where do these calibration factors really come from?

AN219: Output Standing Wave Ratio (SWR) Test Using the TEGAM 1830A RF Power Meter

The TEGAM Model 1830A RF Power Meter coupled with a thermistor power sensor (also known as a thermistor mount) can accurately measure the SWR of a 50 MHz reference. By utilizing a unique function that most modern power meters do not offer; the 1830A allows the user to change the value of the thermistor mounts terminating resistance.

AN220: Measuring RF Power Sensor Nonlinearity

RF power sensor linearity is a commonly misunderstood topic. To obtain the most accurate power measurements, though, you need to understand what linearity is, the sources of nonlinearity, and how to measure the linearity of your RF power sensors.

AN221: Coaxial Flow Calorimeter

How Accurate Are Your RF Measurements? Accurate power measurements on RF signals require a thorough knowledge of the varying nature of the signals under test. We have obtained very good results with this system, improving the uncertainty of a 100W, 1GHz flow calorimeter to 0.43% of full scale. Using this system, through-line wattmeters can be calibrated automatically with an uncertainty of 0.55%.

Signal Source & Amplifier

4040A+5122: Expanded Digitizer Range

The combination of the TEGAM 4040A Differential Amplifier and National Instruments 5122 Digitizer/Oscilloscope creates the widest range measurement system possible in a 3U PXI format.

AN302: Considerations for Selecting a Power Amplifier

This Application Note is intended to help individuals who are not power amplifier experts to understand the basic parameters such as Gain, Bandwidth (BW), Slew Rate (SR), Total Harmonic Distortion (THD), Input Impedance and Current Limit necessary to properly select an amplifier for use in testing and experimentation.

AN400: The Advantages of Multiple Sync Outputs in AWG’s

The purpose of this application note is to provide a summary of the synchronizing outputs of TEGAM's arbitrary waveform generators (AWGs), and to offer a quick-start guide for their operation and use.

AN401: True vs. DDS Arbitrary Waveform Generators

The purpose of this application note is to provide an understanding of the basic differences between True and DDS Arbitrary Waveform Generators. With AWGs, there are two fundamental design variations: DDS (Direct Digital Synthesis) and True (Traditional) Arbitrary Waveform Generators. Each design variation has its own unique advantages and disadvantages. Because the application determines instrument selection, an understanding of the basic differences between True and DDS AWGs is highly beneficial.

AN402: MEMS Optical Profiler

This application note describes how a customer used the TEGAM Model 2350 Dual Channel, High-Voltage amplifier to make a MEMS optical profiling system more effective, and how he applied the system to test and study the reliability of MEMS devices.

AN403: Using Arbitrary/Function Generators to Simulate Polyphase Power Line Waveforms

Polyphase signal generation is required for a broad range of test applications. For example, it is used in condition monitoring or fault detection systems. These tests require the simulation of three-phase sine waves with line frequencies, ranging from 50 - 800 Hz, where fault conditions or high frequency noise are introduced. Three-phase AC power supplies may be considered; however, they are restricted by bandwidth limitations, cost and the inability to recreate real-world waveforms. TEGAM's 2700A series arbitrary/function generators address the synchronization, phase shift and resolution issues and are ideal for simulating pulse, noise, sensor stimuli, speed profiles or faults.

AN404: MEMS Training Station

Describes a station assembled for the North Dakota State College of Science that stimulates MEMS devices and optically measures their response.

AN502: Differential Amplifier Measurements

Making an accurate measurement requires an unbroken chain of signal integrity from the point of connection through the conversion to a numerical value. Application note 502 explains the benefits a differential amplifier provides in a measurement system.

AN503: 4040A Stand Alone Instrumentation Amplifier

A differential instrumentation amplifier is an essential and versatile tool for use in various tests and experiments. For convenience, TEGAM offers a complete package that includes a 4040A instrumentation amplifier, LabVIEW control software and a PXI-1033 chassis.

AN504: Increasing the differential voltage range of TEGAM 4040A

The TEGAM Model 4040A expands the measurement range of PXI digitizers and scopes from 2 mV to 100 V. Although this range appears fairly wide, there are some applications which require a wider range. The measurement range of a PXI system can be expanded up to 1200 Vpk by combining a TEGAM 4040A with x10 or x100 probes.

AN505: TEGAM Power Amplifiers Simplify PSRR Measurements

An interesting note helping engineers make PSRR measurements cost-effectively while simplifying the measurement process and reducing set up time.

Temperature & Humidity

AN600: Food Industry Temperature Measurement

TEGAM has invested many years listening to meat processors around the country and are now introducing a complete line of instrument and probe solutions for the QC Professional.

AN601: TEGAM Temperature Products Aid in Monitoring of Bed Bug Extermination

Bed bugs have quickly become a very important pest of the 21st century, as they have already invaded numerous urban areas including hotels, offices and residences. Increasing the room temperature up to 120-130 °F is found to be effective in killing bed bugs. The TEGAM 819A Series of Thermocouple Thermometer combined with an 8052 Thermocouple Switch Box and 8752 Probe is the fastest and easiest way to measure up to 6 thermocouples.

AN602: Six Ways to Use a Six-way Thermocouple Switch

The TEGAM 819A series of thermocouple thermometers combined with an 8012 Thermocouple Switch is the fastest and easiest way to measure up to 6 thermocouples. This application note explores six different practical uses for the instrument.

AN604: Advantages of Contact Thermometers over Non-Contact/Infrared Thermometers

Use of thermometers to measure temperature has been around for centuries. Understanding the difference between contact and non-contact temperature measurements is vital to health, safety and quality issues in a wide range of industries.

Voltage & Resistance

AN102: How to Properly Zero a Kelvin Klip

To insure proper operation of an instrument with Kelvin Klips, a short (zero) verification should be part of your standard work practices.

AN103: Real Time Wire Plating Thickness Measurement

This application note describes how a customer used the TEGAM Model 1750 High-Speed Programmable Microohmmeter to control the silver plating thickness of copper wire in real-time.

AN105: Real Time Wire Gauge Measurement

This application note describes how a Microohmmeter with offset voltage compensation can assist a manufacturer or processor of electrical wire to measure wire gauge in real time and cost effectively meet the DC Resistance measurements requirements of UL2556.

AN106: Inductive Measurements with a TEGAM Model 1750

Application Note 106 describes a method of compensating the TEGAM Model 1750’s measurement circuit to be able to measure inductive test samples by connecting a capacitor.

AN107: Testing LCD Display Panels with the TEGAM Model 1750

The purpose of this Application Note is to describe how the unique features of TEGAM’s Model 1750 High-Speed, Precise, Programmable Microohmmeter assist in testing large LCD panels.

AN108: TEGAM Test Leads Compatible with Most Manufacturers’ Ohmmeters

Precision measurements require accurate, reliable connections all the way to the device under test. TEGAM manufactures precision instrumentation that measures with parts per million accuracy. TEGAM test leads work with most manufacturers’ four-wire ohmmeters.

AN109: Testing Aircraft Electrical Bonds Ensures Safety and Reliability, Improves System Performance

The bond test determines whether or not an electrical ground has been established between two points. Insuring that electrical bonds in the aircraft are of the highest quality requires the use of an instrument specifically designed to accurately measure very low resistance in demanding environments.

AN110: Bond Tester Helps Protect Wind Turbines from Lightning

Lightning strikes are a leading cause of damage to wind turbines even though they are designed with a lightning arrestor system that conducts the electricity from the tip of the blade, through the nacelle and down the tower to ground. A damaged turbine must be repaired before it can be returned to service generating electricity. Part of the repair includes replacing portions of the lightning arrestor system and verifying that it measures less than the specified resistance all while hanging in the air. This application notes describes a unique solution to the problem that makes it easier to perform this test with equipment that weighs far less than the alternatives.

AN222: Resistance Measurements of Small-Scale and Microscopic Material Samples and Components Using the TEGAM Model 1740

This application note describes a measurement system developed by TEGAM and a customer to make high-accuracy, four-wire milliohm measurements of small-scale or microscopic components and material samples utilizing the TEGAM 1740 microohmeter and a specialized test setup.

AN300: Verify Fenwal Temperature Sensing Elements

This application note provides a general overview of the Fenwal sensing elements and the test methodologies used in conjunction with the TEGAM Model 252 in accurately determining the condition of the sensors. A number of years ago, Fenwal Safety Systems evaluated several LCR meters and selected the TEGAM Model 252 and battery powered 252/SP2596 as their LCR meters-of-choice, for the testing of their temperature sensing elements.

AN301: LCR Meter Measurement Accuracy

LCR meters make taking L, C and R measurements very easy. However, if you want to be certain of the measurement that you have made, you must understand how an LCR meter operates and how the component being tested interacts with the meter.

AN303: The LCR Meter as an Impedance Analyzer

The LCR meter provides a simple and accurate way to measure impedance at a specific frequency point. Impedance analyzers are used to measure and plot the complex impedance of the device under test over a range of frequencies. TEGAM addressed this problem by designing an application which sweeps through user configurable frequency points on the Model 3550 LCR meter. The output is plotted and the measured values are also stored in an Excel file which can be used for further analysis.

AN304: Null Meter Application Guide Introduction

The TEGAM Null Meter Application Guides are written to assist both the new and experienced user of high-sensitivity Null Meters/Nano-Voltmeters. For the new user, the Application Guides provide a basic understanding of the fundamentals of measurement process that use Null Meters. For the experienced user, the Application Guides provide a refresher on fundamentals but more importantly help the user moving from the use an older model null meter to the TEGAM AVM-2000.

AN305: Input Bias Current Compensation

This Application Guide describes the sources of input bias current on a high sensitivity instruments such as a null meter, the impact input bias current can have on measurements and how the user compensates for input bias current to minimize its impact on measurements.

AN307: Noise Reduction and Filtering Techniques

This Application Guide discusses the use of filtering to improve null measurements when noise on the signal source makes measurements difficult or introduces error. This note also helps the experienced user compare a null meter with variable filtering with one that has fixed filtering.

AN308: High Sensitivity Bridge Connections

This Application Guide discusses suggested instrument interconnections and supplemental filtering to allow maximum resolution when the AVM-2000, or other very high sensitivity null meters, are used in conjunction with such instruments as Reference Dividers, Kelvin Varley Dividers and other high-impedance ratio dividers.

AN309: Input Offset Voltage Compensation

This Application Guide describes the sources of input offset voltage on a high sensitivity instruments such as a null meter, the impact input offset voltage can have on measurements and how the user compensates for input offset voltage to minimize its impact on measurements. The experienced user will find this discussion helpful in understanding potential differences in measurements between various null meters.

AN310: Rationalizing Null Readings at Low Levels

This Application Guide discusses the problems encountered when comparing nulls, especially nulls made in the micro-volt and nano-volt regions, between two null meters. Frequently minor differences between two different null meters, the minor differences between instrumentation setups and other environmental issues contribute to those differences. This Application Guide is written to help a null meter user rationalize the differences and to take corrective actions, where possible, to reduce the differences between readings.

AN311: Analog Meter Anti-Static Procedure

This Application Guide discusses the need and procedure for using an anti-static control solution on sensitive analog meter movements such as the one found in the AVM-2000 Nullmeter. Although common knowledge when most instruments used analog meter movements, the need to remind users of this procedure compensates for techniques lost in the world of digital displays.