Tim Jackson Gives an LCR-T4 Component Tester an Overhaul with Rechargeable Battery, Smart Case

Maker and self-described "smith of many trades" Tim Jackson has taken a cheap transistor tester and improved its usability — by tweaking the hardware, updating the firmware and installing a rechargeable battery in a custom case.

"This [guide] is about upgrading a Chinese version (LCR-T4) of the transistor tester," Jackson explains, referring to a common tool which allows for transistors, diodes, triodes, capacitors, and other components to be inserted into a socket and their characteristics read out using an on-board display. "There are more mods that can be done to the transistor tester, hopefully this [guide] may help you decide if you want to go further with the project."

Jackson's project builds on the work of Karl-Heinz Kübbeler, who made the source code for the microcontroller-driven LCR-T4 and other transistor tester models available on GitHub. Jackson's variant includes new code designed to support a rechargeable battery — replacing the 9V PP3 which usually powers the LCR-T4.

Firmware support is only half the battle, though, and Jackson has also provided instructions on modifying the hardware to add the hardware required to handle a 3.7V lithium-polymer battery using a low-cost HW-107 charger module and boost converter which live with the tester and battery in a smart 3D-printed case. Finally, Jackson guides the reader on using two capacitors of known value and a couple of lengths of bent wire to calibrate the tester for more accurate readings.

The whole guide is published on Instructables, while the modified firmware source code is available on GitHub under an unspecified license; pre-built binaries are available on the Instructables page for those who would prefer not to build the firmware from scratch.