Finding broken wire inside wall or over insulator is very difficult and here is the simple solution to find the broken wire, here we have used only transistors to identify the broken wire location. By using simple broken wire detector we can identify the presence of current flow, if there is no current flow then buzzer and LED becomes off.
Normal wire can be used as antenna to pickup electromagnetic force (EMF) from the current flowing wire. Three stage Transistors act as amplifiers and strengthens detected signal from current flowing wire and makes Buzzer to produce beep sound and LED to blink. If there is no current flow then Buzzer and LED stays in turn OFF position.
Circuit Diagram
Components Required
Construction & Working
Take a short length wire as antenna and connect it to the base terminal of Q1 transistor, this Q1 transistor biased through 100KΩ Resistor and emitter terminal connected to Base of Q2 transistor this is biased through 10KΩ Resistor then emitter terminal of Q2 is connected to the base of Q3 transistor, Buzzer and LED Connected at the collector terminal of Q3 through 100Ω Resistor, whole circuit is biased with 9V battery.
BC547 (NPN) pin details
When the antenna wire placed near current flowing wire it will pickup EMF signal and after amplification by three transistors Buzzer and LED makes indication. If the wire broken then there will be no EMF and hence there is no indication from buzzer and LED.