NON-CONTACT POWER MONITOR

NON-CONTACT POWER MONITOR By: D. MOHAN KUMAR   Here is a simple non-contact AC power monitor for home appliances and laboratory equipment thatshould remain continuously switched-on. A fuse failure or power breakdown in the equipment going unnoticed may cause irreparable loss. The monitor sounds an alarm on detecting power failure to theequipment. The circuit is built around CMOS IC CD4011 utilising only a few components. NAND gates N1 and N2 of the IC are wired as an oscillator that drives a piezobuzzer directly. Resistors R2 and R3 and capacitor C2 are the oscillator components. The amplifier comprising transistors T1 and T2 disables...

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