Analog Discovery Impedance Analyzer
Reference Manual
The Impedance Analyzer Instrument in WaveForms is made easier to use by the reference
resistors and relays that come pre‐loaded on the Impedance Analyzer board. The Analog
Discovery can automatically select the most appropriate component for the job that it needs to
do. The Impedance Analyzer is equipped with the 2×15 Analog Discovery connector, which
makes it compatible with Analog Discovery Legacy, Analog Discovery 2, and Analog Discovery 2‐
NI Edition.
Note: Use of the Impedance Analyzer requires WaveForms version 3.8.2 or later.
Overview
Features
Equipped with automatically selectable reference resistances
Compatible with the Analog Discovery Legacy, Analog Discovery 2, and Analog Discovery NI‐
Edition
Allows auto‐scaling
Compatible Products
The Analog Discovery Impedance Analyzer is compatible with the following:
Analog Discovery Legacy
Analog Discovery 2
Analog Discovery 2‐NI Edition
About this Document
This reference manual applies to Revision A of the Analog Discovery Impedance Analyzer.
Functional Description
Connectors and Jumpers
J1 ‐ 2×15 Analog Discovery connector ‐ Interfaces the Impedance Analyzer with the Analog
Discovery
J2 ‐ 1×2 Terminal Bloc ‐ Used for connecting in circuit the unknown impedance
Digital Pins used for configuration
The Analog Discovery's digital I/O pins are used to control the relays in order to select the
needed value for the reference impedance. Each relay driver uses two I/Os to control one relay.
Measuring the impedance
The Analog Discovery Impedance Analyzer is used to analyze capacitive and inductive elements.
It uses the WaveGen 1, Oscilloscope device instruments, and a reference resistor.
The impedance analyzer circuit is constructed as in the circuit below. Load represents the
inductive or capacitive item to be analyzed and Resistoris the reference resistor that is already
loaded on the board. The resistor value depends on the load value and frequency.
The approximate resistor needed for different loads are the following:
Capacitance
Ref Resistor
Inductance
100 pF
1 MΩ
1 nF
100 kΩ
10 nF
10 kΩ
100 nF
1 kΩ
1 uH
1 uF
1 kΩ
10 uH
10 uF
100 Ω
100 uH
100 uF
10 Ω
1 mH
Power
The device is powered through the 5V user power supply from the Analog Discovery. It requires
approximately 25mA
Software Support
The Analog Discovery Impedance Analyzer is controlled with the Analog Discovery through the
use of WaveForms' Impedance Analyzer instrument. When the instrument is started, the Scope
and WaveGen are stopped and their status shows “Busy”. The Impedance Analyzer takes
control over these instruments while running.
When using the Analog Discovery Impedance Analyzer module, select “Adapter” in the
interface, after the resistor field. The application will use the power supplies and digital I/Os to
control the module to switch between the resistor values: 10R, 100R, 1k, 10k, 100k, 1M.
Additional Information
WaveForms can be downloaded from the WaveForms Resource Center.
Documentation and installation instructions can be found in the WaveForms Reference Manual.
The Analog Discovery Impedance Analyzer Schematic can be found here.
https://reference.digilentinc.com/reference/add‐ons/impedance‐analyzer/reference‐manual 6‐19‐18
