Here is the simple AC Current Sensor. It is useful for checking the power in mains wiring especially the broken points in concealed wiring. Whenever the probe gets close to AC Mains the LED Glows and buzzer beeps. It can detect the line from a distance of upto 31 cm.
The circuit uses an n-channel FET BFW11 for detecting the mains voltage.
Assemble the circuit on a general purpose circuit board and use a miniature DC Buzzer with internal oscillator and transparent LED.
Use 10cm steel rod or a telescopic antenna as the probe.
Now, you are done with your noise making AC Current Sensor.
Thanks for the compliment and suggestion.