LOGIC PROBE CONSTRUCTION

Constructing a logic probe

required for this practical :
• 2 wires, one red and one black
• 2 resistors on 1KΩ
• 2 alligator clips one red one black
• 2 LED's one red and one green
• a brass rod 150 mm long
• 100mm plastic tube
• shrink tubing: black 2.4mm diameter 300mm long

red 6.4mm 175mm long

black 12.7mm 125mm long

I soldered the 2 LED's to the each of the resistors and to the wires(as in diagram A). these I then

shrink insulated the resistors and the LED for support

I filed down the brass rod tip to be pointed, tined an area of the rod to make soldering the LED easier. Covered the areas on either side of the tined section of the brass rod with heat shrink.Next, I soldered the uninsulated legs of the LED on the tinned section of the rod and hot glued it together to give extra support.(as in diagram B)

used blue heat shrink to support the resistors and LED's onto the rod as well.

The plastic tubing needed to have a groove cut out on it to a length as long as the two LED's

are in line on the brass rod and I slid it to fit as shown below

for appearance, I used the black shrink tubing to cover the plastic tubing as well as the pointed end side of the LED's to look like the diagram below.(E). the two wire red and black I twisted around each and soldered alligator clips at each end to complete the task.