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In highway road light is glow even no motor or car on the highway. This will misuse of
road light and electricity, for overcome this problem we introduce this circuit. We make
power on the lights in safe distance till whole night. And some light will on automatically
when any motor or car comes in the road. And off automatically after it will cross exit out
sensor.
First we convert 220V ac to 12 v ac with the help of step down transformer, over project
work in dc supply so we convert 12v ac to 12 v dc, for this we use bridge rectifier, it is
consist with four diode 1N4007, and make a ripples free dc supply with the help of 1000
uf /25 electrolytic capacitor, our both NE555 ics is waiting for input, our first in LDR get
interrupted by vehicle it give signal to first NE555 ic, it become on and give output from
pin-3 to first transistor, it will go the ULTRA BRIGHT LED’S, when vehicle pass throw
second out LDR it give signal to second NE555 ic, it will on and give signal to second
transistor, it become on and give signal to first IC it will become off, and it will also off
the first transistor, if will automatically of the ULTRA BRIGHT LED’S.
Basic Electronics
When a beginner to electronics first looks at a circuit board full of
components he/she is often overwhelmed by the diversity of do-dads. In
these next few sections we will help you to identify some of the simple
components and their schematical symbol. Then you should be able to call
them resistors and transistors instead of “Whatchamacallits”.
Electronic component are classed into either being Passive devices
or Active devices.
A Passive Device is one that contributes no power gain (amplification)
to a circuit or system. It has not control action and does not require any
input other than a signal to perform its function. In other words, “A
components with no brains!” Examples are Resistors, Capactitors and
Inductors
Active Devices are components that are capable of controlling voltages
or currents and can create a switching action in the circuit. In other
words, “Devices with smarts!” Examples are Diodes, Transistors and
Integrated circuits. Most active components are semiconductors.
Resistors:
This is the most common component in electronics. It is used mainly to
control current and voltage within the circuit. You can identify a simple
resistor by its simple cigar shape with a wire lead coming out of each end. It
uses a system of color coded bands to identify the value of the component
(measured in Ohms) *A surface mount resistor is in fact mere millimeters in
size but performs the same function as its bigger brother, the simple
esistor. A potentiometer is a variable resistor. It lets you vary the resistance
with a dial or sliding control in order to alter current or voltage on the fly.
This is opposed to the “fixed” simple resistors.
Resistor values - the resistor colour code
Resistance is measured in ohms, the symbol for ohm is an omega .
1 is quite small so resistor values are often given in k and M .
1 k = 1000 1 M = 1000000 .
Resistor values are normally shown using coloured bands.
Each colour represents a number as shown in the table.
Condensors/Capacitors:
Capacitors, or "caps", vary in size and shape - from a small surface mount model
up to a huge electric motor cap the size of a paint can. It storages electrical
energy in the form of electrostatic charge. The size of a capacitor generally
determines how much charge it can store. A small surface mount or ceramic cap
will only hold a minuscule charge. A cylindrical electrolytic cap will store a much
larger charge. Some of the large electrolytic caps can store enough charge to kill
a person. Another type, called Tantalum Capacitors, store a larger charge in a
smaller package.
This is a measure of a capacitor's ability to store charge. A large
capacitance means that more charge can be stored. Capacitance is
measured in farads, symbol F. However 1F is very large, so prefixes are
used to show the smaller values.
Three prefixes (multipliers) are used, µ (micro), n (nano) and p (pico):
• µ means 10-6 (millionth), so 1000000µF = 1F
• n means 10-9 (thousand-millionth), so 1000nF = 1µF
• p means 10-12 (million-millionth), so 1000pF = 1nF
Capacitor values can be very difficult to find because there are many
types of capacitor with different labelling systems!