Characterizing electrical components with Flojoy

Using a Keithley Sourcemeter

This is the third in a series on test & measure automation using Flojoy and Tektronix instruments.

See Part 1 on how to characterize a filter with a Bode plot and Part 2 on how to decode I²C data.

Flojoy Introduction

Flojoy is a modern test and measurement (T&M) app that uses Python. Flojoy has the ease of use common with no-code applications. It also offers advanced users the option to create custom Blocks of Python code for specialized applications. Here we show a use case for using Flojoy with Tektronix instruments.

IV curves

IV curve (AKA Current–voltage characteristic) is an important tool in characaterizing electrical components such as diodes, transistors, etc. Solar cells are type of device where IV curves are important. In an IV curve, the voltage across a device is varied and the resulting current is measured for each voltage.

Figure 1: IV curve of a transistor with varing gate voltages.

Setup

The first step is ensuring Flojoy can see the sourcemeter we will be using. See Part 1 for a guide on how to make a hardware connection in Flojoy. The second step is the physical setup of the components and wires. This setup is designed to test two components, but can easily be changed to test the number of components required. This app requires manually changing the wiring between components (Figure 2). An automated switch, like a relay, could also be used for this purpose as well. Once the physical setup is finished, the app can be loaded.

Figure 2: The circuit setup. The red wire on the left must be switched between the two components when the beep occurs.

Ensure you set the parameters for you requirements. The most important parameter is to select the instrument as shown in Figure 2. For example, the voltages for the IV curves are set in the IV SWEEP blocks.

Figure 3: The Flojoy app for performing two IV curves. The TIMER block delays the app while the wire is switched between the two components.

Running the app

Once the parameters are all correctly set, you can run the app. As you can see, the components have the typical features such as linear, saturated, and breakdown regions.

Figure 5: Here are the results for the transistor and diode. Note the typical regions for these types of components.

Congrats you’ve extracted an IV curve for some electronic components! If you had any difficulties here, or any comments or suggestions please contact us.