20-01-2012, 02:10 PM
INVISIBLE OPEN WIRE DETECTOR
[attachment=16337]
Portable loads such as video cameras,
halogen flood lights, electrical
irons, hand drillers, grinders,
and cutters are powered by connecting
long 2- or 3-core cables to the mains
plug. Due to prolonged usage, the power
cord wires are subjected to mechanical
strain and stress, which can lead to internal
snapping of wires at any point. In
such a case most people go for replacing
the core/cable, as finding the exact location
of a broken wire is difficult. In 3-core
cables, it appears almost impossible to detect
a broken wire and the point of break
without physically disturbing all the three
wires that are concealed in a PVC jacket.
The circuit presented here can easily
and quickly detect a broken/faulty wire
and its breakage point in 1-core, 2-core,
and 3-core cables without physically disturbing
wires. It is built using hex inverter
CMOS CD4069. Gates N3 and N4
are used as a pulse generator that oscillates
at around 1000 Hz in audio range.
The frequency is determined by timing
components comprising resistors R3 and
R4, and capacitor C1.
