Design, Construction and Characterisation of Domestic Live-Wire Detector Device

Abstract

Domestic Live-wire Detector Device was designed, constructed and characterised in this research work. The device consists of the Detecting Unit, the Oscillator Unit and the Display Unit. The design and construction of the device is centred on 4069UBC inverter chip with fourteen inverter circuits. Detecting unit is implemented with the IC pin1 through an aerial track made of copper conductor, and also comprises pins 2,3,4,5,6,12 and13, resistors R1, R2, R3 and variable resistor VR. The oscillator unit which comprises the pins 8,9,10 and 11 of the chip has resistors R5 and R6 and capacitor C3 as frequency elements and is designed to operate at audible frequency of 50Hz. When a.c. field is detected, the diode incorporated into this unit will now be reverse-biased and allows the oscillator unit to run. It is the output of the oscillator unit that drives the buzzer directly which allows a sound to be heard. The display unit comprises two LEDs; the green LED1 lights when the power switch is turned on, which indicates that the circuit is active while the red LED2 lights through transistor switch TR1-C1914 whenever the device senses an a.c. electromagnetic field. This device is powered by a 9v battery.