Logic Probe

This is the schematic i used to build my very first logic probe. It helped me to better understand how a transistor works. When the probe portion of the probe is idling, the LED is noticeable dim.
When the probe to connected to a point that is low, the LED will shut off completely because no current is found.
When the probe portion finds a point with current greater than 3 volts, the LED will brightly shine.
Probes are pretty handy when debugging a circuit. Since you really can't see where exactly the electricity is flowing, it is difficult to find why some times things don't work when youre assured your circuit is built right. It allows the user the ability to quickly find when the power to flowing though


Here is what my logic probe looks like at the very end. I hot glued the top and not the bottom because i was pretty proud of a soldering and want something always reflect on to do better.