• This is the essential tool in every ones tool box for fhen designing or fixing any digital circuit. The circuit is build around lm339 voltage comparator with selection switch for TTL and CMOS circuits.
  
  The case files have opening for 3 digit 0.36 voltage meter that are available through eBay or Aliexpress and many other on line stores
  
  The design of the probe is very easy to understand and has very few components, it is however layed out using 0805 SMD components and for some it may be bit challenging to solder
  
  
  Versions of the boards are available on our Tindie store

  
   

  Features

     Wide input voltage
     CMOS and TTL level selections
     Small outline for very easy handling
     simple passive components - No microcontroller programming
  
   

  Documents

    Schematic
    PCB (easyEDA)
    3D Top STL file   (LED)
    3D Bottom STL file