Snap a 9V Battery to the battery clip. The Letter L should be displayed on the 7 Segment LED Display. Next soldered a red wire on the pcb where "Probe...
The following instructions will allow you to build a practical test tool for troubleshooting and analyzing digital and microcontroller circuits. The complete Assembly and Instruction Manual can be downloaded from the the following web link:Don's Projects
Step 1: Bill Of Materials
Here's the components needed to build the Logic Probe shown in the Bill of Materials (BOM) picture.