Continuity And Component Tester

This continuity tester gives a beep sound if detect an electric current conduction between its probes. Here is the schematic diagram of this audible cable/component tester:

Audible indication gives the benefit of “free eyes” compared to LED or other visual indication. Your eyes will normally have to keep watching on what is being tested,  no more eyes for watching any instrument’s indicator, and this sonic indication will save your life!