25-01-2012, 03:27 PM
PROTECTION FOR YOUR ELECTRICAL APPLIANCES
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Here is a very low-cost circuit to
save your electrically operated
appliances, such as TV, tape
recorder, refrigerator, and other
instruments during sudden tripping and
resumption of mains supply. Appliances
like refrigerators and air-conditioners are
more prone to damage due to such
conditions.
The simple circuit given here switches
off the mains supply to the
load as soon as the power
trips. The supply can be
resumed only by manual
intervention. Thus, the
supply may be switched on
only after it has stabilised.
The circuit comprises a
step-down transformer
followed by a full-wave
rectifier and smoothing
capacitor C1 which acts as
a supply source for relay
RL1. Initially, when the circuit is switched
on, the power supply path to the stepdown
transformer X1 as well as the load is
incomplete, as the relay is in de-energised
state.
