AN-1. Measuring Inductor and Transformer Impedance.  (Click to Open)

This application note shows how to measure the impedance characteristics of an inductor and a transformer.  The transformer characteristics, although inductive in nature, presented a slightly different measurement challenge because in addition to the DC resistance, two inductances, magnetizing inductance, Lm and leakage inductance, Ll must be considered.  Physical models for both the inductor and transformer, along with component values were derived and can be used in simulation packages to better predict theoretical circuit behavior.

<AN-2.   Measuring Power Supply Control Loop Stability.  (Click to Open)

This application note describes a method to measure the open-loop frequency response (transfer function) of a switching power supply using the Circuit Sleuth SA-40 network analyzer and injection transformer.  A standard feedback control system block diagram was used to illustrate the mathematical nature of the open-loop response and an example schematic was partitioned off to show how the circuit configuration relates to the control block diagram.  The schematic was also used to determine the best location in the circuit for the signal injection resistor.  

<AN-3.  Measuring Capacitor Impedance and ESR.  (Click to Open)

This application note shows how to measure the impedance characteristics of a commercially available SMT electrolytic capacitor.  The capacitor value, as well as its equivalent series resistance (ESR) is measured.  A capacitor physical model, suitable for use in a circuit simulation, was derived from the measurements. 

<AN-4.  Frequency Response Analysis of Op Amp Characteristics. (Click to Open)

The frequency response plots discussed in this application note will focus on the most common operational amplifier circuits and specifications.  The first section will discuss how the gain bandwidth product of an op amp affects the inverting and non-inverting amplifier configurations.    The second section will discuss the differential amplifier and common mode rejection. 

<AN-5.  Measuring Low Value Resistance.  (Click to Open)

This application note describes resistance measurements in the 0.001 to 0.1 ohm region and illustrates the measurement of a 0.005 ohm resistor.  The measurement of such low value resistances requires techniques that minimized or account for stray resistances due to wire lead length both for the stimulus signal path and the physical location of the test probes on the DUT.  The sensitivity of the measurement was demonstrated by placing the test probes at a specified position, then in a secondary position and comparing the two measurements. 

<AN-6.  Characterization of an RLC lowpass filter.  (Click to Open)

Commercial inductor and capacitor values are known for extremely wide tolerances.  This leads to the conclusion among engineers that it is difficult to get measurements to agree closely with the theoretical calculations.  This application note illustrates that when components are characterized, accurate theoretical predictions and simulations are possible.  By this, the design has increased reliability, improved quality and outstanding performance.

AN-1. Measuring Inductor and Transformer Impedance.

AN-2. Measuring Power Supply Control Loop Stability.

AN-3. Measuring Capacitor Impedance and ESR.

AN-4. Frequency Response Analysis of Op Amp Characteristics.

AN-5. Measuring Low Value Resistance.

AN-6. Characterization of an RLC lowpass filter.