Curve tracers

Curve tracing is a classic way to learn more about many electronic components. Curve tracing is essentially a means of making a graph of current (I) versus voltage (V) called an I-V curve, to display the basic characteristics of an electronic device. I-V curves of the components are helpful in understanding their limitations and nonlinear operation. Such curves are also useful in establishing circuit models and for determining bias points, load lines and boundaries of the devices.

Nowadays curve tracing seems to be a somewhat lost art, as many engineers rely only on the curves given by the device manufacturer. As any electronics hobbyist knows, device actions in real life will (often largely) vary from the model that defines its operation. Many electronics struggle with Tracing Curves, whether it be the smooth VI line of a capacitor or the voltage of a collector transistor against the current curve.

AC curve tracing is the most common way to do curve tracing. You need an AC voltage source, a transformer, some resistors and a DC-coupled oscilloscope to measure two terminal devices.

Component Tester – Curve Tracer

Simple Component Tester

How to Use an Oscilloscope and Signal Generator as a Component Tester / Curve Tracer

For effective curve tracing of transistors, a somewhat more complicated testing device is needed. A good transistor tester does the curve tracing with many different base current values.

Here are some project links:

Create Your Own I-V Curve Tracer
https://circuitcellar.com/research-design-hub/create-your-own-i-v-curve-tracer/
In this article I will describe an economical way of obtaining the I-V curves of two- and three-terminal devices, using a PC, an economical USB oscilloscope (Hantek 6022BE), a simple circuit and a bit of Windows software. It’s a project that should appeal to almost anyone involved in electronics.

Simple Curve Tracer Circuit for Resistor, Diode, and Transistor
https://www.circuits-diy.com/simple-curve-tracer-circuit-for-resistor-diode-and-transistor/

Building A Curve Tracer
https://www.paulvdiyblogs.net/2017/12/building-curve-tracer.html

DIY Generic Curve Tracer
https://www.electronics-lab.com/diy-generic-curve-tracer/
Using the on-board Phase Shift Oscillator to provide the test signal, passive and active parts can be tested.

Simple but effective Transistor Curve Tracer circuit.
https://www.eddybergman.com/2017/06/simple-but-effective-transistor-curve.html
This curve-tracer uses only 6 transistors and produces a beautiful curve display on an oscilloscope in X-Y mode

Transistor Curve Tracer
https://www.instructables.com/Transistor-Curve-Tracer/
For a PNP or NPN transistor it plots Vce (the voltage between the collector and emitter) versus the current flowing into the collector. A line is drawn for each different base current – e.g. 0uA, 50uA, 100uA, etc. For a MOSFET it plots Vds (the voltage between the drain and source) versus the current flowing into the drain. A line is drawn for each different gate voltage – 0V, 1V, 2V, etc.

22 Comments

  1. Tomi Engdahl says:

    How To Build the Amazing CHEAP DIY Huntron Tracker Octopus PCB Tester Curve Tracer $20 or less
    https://www.youtube.com/watch?v=nWCZCLGtyDU

    The Huntron Tracker is something of a legend in the electronics repair community. Second hand ones are hard to find and attract a large price tag! I used one back in the 1980s and they are really good for fault finding on all sorts of PCBs. Let’s see if we can build a Huntron Tracker clone using a mixture of salvaged components and cheap off the shelf parts, the aim is to keep the cost down to around $20

    00:00:00 Introduction
    00:00:38 Update on the $1 Short Finder Project
    00:02:02 The PCBWay Ruler
    00:04:07 The Device Under Test
    00:05:07 The Legend Of The Huntron Tracker
    00:07:48 HZ 65 Component Tester
    00:16:05 DIY HZ 65 Add-on
    00:17:29 Fault Finding With The Huntron Tracker
    00:19:55 Reverse Engineering
    00:28:58 The Schematic
    00:30:42 The 110 Ohm Fuse!
    00:31:23 How It Works
    00:36:37 Designing the $20 Huntron Tracker
    00:41:36 Building the $20 Huntron Tracker
    00:53:57 Setting The Trimmer Pot
    00:54:59 Testing the $20 Huntron Tracker
    00:58:10 Conclusion

    Reply
  2. Tomi Engdahl says:

    Comparing a Huntron Tracker and Multimeter
    https://huntron.com/news/comparing-huntron-tracker-dmm/

    Test by Comparison
    Troubleshooting is also much easier if a known-good board is available so that visual and signal comparisons can be made. Lack of a comparative board or documentation makes the challenge more daunting. This is where the Huntron Tracker proves to be an essential tool for troubleshooting.

    The Huntron Tracker is diagnostic tool to enhance your circuit board test capabilities. It is an important part of any electronic repair environment. Huntron Tracker power-off circuit board test uses analog signature analysis to detect and isolate faulty components. By comparing Tracker signatures from a working printed circuit board (PCB) to the signatures of a non-working PCB, you can troubleshoot down to the component level.

    https://huntron.com/products/trackers.htm

    Reply
  3. Tomi Engdahl says:

    UCE-CT220L Fault Locator & Curve Tracer
    https://www.youtube.com/watch?v=g58ZwIwJPf8

    I-V test method is widely used in the World for PCB repairing. It can be located faults with this product on unpowered PCBs. You don’t need electrical models for the components used on the PCB.
    The Tracker’s features variable range parameters resulting in over 30 combinations of voltage, source resistance and frequency.

    UCE-CT220L / Dual Mode
    https://www.youtube.com/watch?v=aDdhsh7el0s

    I-V test method is widely used in the World for PCB repairing. It can be located faults with this product on unpowered PCBs. You don’t need electrical models for the components used on the PCB.
    The Tracker’s features variable range parameters resulting in over 30 combinations of voltage, source resistance and frequency

    Reply
  4. Tomi Engdahl says:

    Semiconductor Curve Tracing Using Function Generator/AWG
    https://www.youtube.com/watch?v=dn_UA3dvP_4

    Here I showed a couple of methods to implement a curve tracer using Function generator/AWG.

    00:00 Introduction
    01:12 Standalone Curve Tracing Circuitry
    01:45 Method One
    03:06 Method Two
    05:26 Measurement Setup with Method One
    07:43 NPN transistor Curve Tracing/Parameters Adjustment
    13:25 N-Channel MOSFET Characteristics Curve
    14:28 NPN transistor Characteristics Curve using Method Two/Conclusion

    Reply
  5. Tomi Engdahl says:

    Curve Tracer Video
    https://www.youtube.com/watch?v=KGuAy1L6BSs

    This is a video recording of a PowerPoint presentation made at the Mid-Atlantic Antique Radio Club (MAARC) March 15th, 2020 monthly meeting on the subject of Curve Tracers by MAARC member and Vice President Dave Rossetti. Featuring the Fairchild/Systron-Donner 6200B, the presentation addresses what Curve Tracers are, and how they can be used to measure the performance of semiconductors and vacuum tubes. It addresses various Curve Tracer availability and features. The PowerPoint presentation is available on the MAARC.ORG website under ‘Monthly Meeting Presentations.

    Reply
  6. Tomi Engdahl says:

    Transistor Curve Tracer
    https://www.youtube.com/watch?v=AIMJ0stkOKE

    Rudimentary transistor curve tracer using a function generator, collector load resistor, variable base current supply and oscilloscope.

    Reply
  7. Tomi Engdahl says:

    Measuring the Collector Characteristic Curves and Gain of Various Transistors Using a Curve Tracer
    https://www.youtube.com/watch?v=_BpeoC8lcic

    The video demonstrates how to measure the DC gain (Beta) of various types of Bipolar Transistor Using a Heathkit Curver Tracer. It also discusses how to measure other transistor parameters including VCE breakdown voltage and linearity.

    Reply
  8. Tomi Engdahl says:

    Using the Tektronix 575 – How It Works – Part 1
    https://www.youtube.com/watch?v=hc1_8XOmFTQ

    In this video the various functional blocks of the 575 are discussed. This is part of a series about using a curve tracer to measure various parameters of semiconductor devices.

    Reply
  9. Tomi Engdahl says:

    Putting Random Things on Curve Tracers Russian Tunnel Diodes
    https://www.youtube.com/watch?v=sbcC1qGRMEY

    In this video we look at some parts on a curve tracer Tunnel diodes and some other components. LED’s were harmed in the making of this video. Russian TD’s can NOT be used as a replacement for D180 in a type 284 they are not dimensionally compatible.

    Reply
  10. Tomi Engdahl says:

    Huntron® Trackers®
    Power-off Diagnostic Tools for Circuit Board Troubleshooting
    https://huntron.com/products/trackers.htm

    Reply

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