Home Projects Test and measurement TraId - TransistorType & Polarity Identifier


TraId - TransistorType & Polarity Identifier
author: Small Room Labs - Kuala Lumpur, Malaysia

TraId is a simple transistor tester and pinout identifier. It is able to test bipolar transistors as well as N-mosfet and P-mosfet. Result are displayed using LEDs driven by a PIC16LF1503 microcontroller.


The board is using a 14 pin PIC16LF1503 (less than a dollar in singles) and runs on a single CR2032 battery. I'm using a 1K and a 300K resistor connected to each of the three transistor pins, putting out either 0 or 3 volts via the resistors and analyzing the resulting voltages using the PIC ADC.

The firmware, written in C, uses 1.3K of the available 2K so there's room for some more additions and improvements down the road.

There's no power switch on the board, the PIC simply goes into deep sleep after a while and is awakened by a press on the reset button.

The pic have a spare pin connected to the via below pin 7. I have it connected to a 2x8 LCD with a 1-wire serial "roman black" backback as described in this thread.


click on schematic for full resolution

 PCB Design

PCB top layer


PCB bottom layout


3D PCB rendering


Download Project files (Cadsoft Eagle)

Download PCB Gerber files

Download Firmware


120x90 spot



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