Radiation sensor

here is the simple tool to check the degree of radiation from an electric or electronic instrument
.The led s in the circuit will give a running light pattern at the momemt the circuit sences electromagnetic
radiation from the device.it can detect the radiation from the computer or telivision from a distance of 2feet or more

pyro electric fire alarm

Here is an ultra-sensitive fire
sensor that exploits the direct
piezoelectric property of an
ordinary piezo element to detect fire.
The lead zirconate titanate crystals in
the piezo element have the property
to deform and generate an electric
potential when heated, thus converting
the piezo element into a heat sensor.
The circuit described here is very
sensitive. It gives a warning alarm if
the room temperature increases more
than 10°C. The entire circuit has two
sections—the sensor and the power
supply section.

protection for your electrical appliances

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.

power failure alarm

Description
This is a very basic alarm designed to let you know when the electricity supply fails. The
alarm is powered from a battery which uses no current consumption at all in standby, a
battery should therefore last its full shelf life.

Pc over heat alarm

If your PC overheats, it could
damage its expensive components.
Here’s a circuit that warns you of
your PC getting heated.
Today’s computers contain most
of the circuitry on just a few chips
and reduced power consumption is
a byproduct of this LSI and VSLI
approach. Some PCs still have
power supplies that are capable of
supplying around 200W, but few
PCs actually consume power to this
extent.
On the other hand, apart from
some portable and small desktop computers
that use the latest micro-power
components, most PCs still consume
significant amount of power and generate
certain amount of heat.

Mini ups system

This circuit provides an uninterrupted
power supply (UPS)
to operate 12V, 9V and 5V
DC-powered instruments at up to 1A
current. The backup battery takes up
the load without spikes or delay when
the mains power gets interrupted. It
can also be used as a workbench power
supply that provides 12V, 9V and 5V
operating voltages. The circuit immediately
disconnects the load when
the battery voltage reduces to 10.5V to
prevent deep discharge of the battery.
LED1 indication is provided to show
the full charge voltage level of the battery.
miniature white LEDs (LED2 and
LED3) are used as emergency lamps
during power failure at night.

Lpg gas leakage detector

LPG gas is supplied in pressurised
steel cylinders. As this gas
is heavier than air, when it leaks
from a cylinder it flows along floor
and tends to settle in low spots such
as a basement. This can cause fire or
suffocation if not dealt with.
Here is a circuit that detects the
leakage of LPG gas and alerts the user
through audio-visual indications.