are brief explanations of some of the parts used within the robots:
Resistor A Resistor is an
electronic component that is deliberately designed to restrict the flow of
electrical current in a circuit. The higher the resistance value, the more
it restricts the flow. The resistor will give the circuit a stable current
thus giving protection to sensitive elements within a circuit from damage.
The resistor is measured by its ability to offer resistance and this is defined
is Ohms Law? The Law basically brings together the relationship between Voltage (V), Resistance ( R) and Current (I) as follows:
(R) (ohm W)
Difference (V) in volts
Current (I) in amperes
The official definition is:A resistor offers a resistance of
one ohm Ω if a potential difference of one volt drives a current of one ampere through it.
What's an ampere? The unit for current, the symbol for the ampere is (A).
What's Potential difference? Potential difference is a difference in electrical potential energy across each resistor and across a battery.
do you determine the resistance of a resistor? Resistors
are colour coded for easy reading. To determine the value of a given
resistor look for the gold or silver tolerance band and rotate the
resistor as in the photo above. (Tolerance band to the right). Look at
the 1st colour band and determine its colour. This maybe difficult on
small or oddly colored resistors. Now look at the chart and match the
"1st & 2nd colour band" colour to the "Digit it represents". Write
this number down. Now look at the 2nd colour band and match that colour
to the same chart. Write this number next to the 1st Digit. The Last
colour band is the number you will multiply the result by. Match the
3rd colour band with the chart under multiplier. This is the number you
will multiple the other 2 numbers by. Write it next to the other 2
numbers with a multiplication sign before it. Example: 2 2 x 1,000. To
pull it all together now, simply multiply the first 2 numbers (1st
number in the tens column and 2nd in the ones column) by the
Resistor Colour Code Chart
1st & 2nd
X1,000 or 1K
X10,000 or 10K
X100,000 or 100K
X1,000,000 or 1M
Silver is divided by 100
Gold is divided by 10
⋅Gold = 5%
⋅Silver = 10%
⋅None = 20%
are several types of capacitors but they all perform the same basic
function; that is to store electric charge. Used in electronic
circuits; it consists of two or more metal plates separated by an
insulating layer called a dielectric. Itscapacitanceis
the ratio of the charge stored on either plate to the potential
difference between the plates. The SI unit of capacitance is thefarad,but
most capacitors have much smaller capacitances, and the microfarad (a
millionth of a farad) is the commonly used practical unit. Electrolytic
and Mylar capacitors are used in this electronics kit. We use a
combination of resistors and capacitors to suppress voltage
fluctuations in the power supply and set the time period on the timer.
Capacitors can also be used to remove any alternating current
components within a circuit.
capacitors have an insulator, which is a flexible mylar film, so a
large area can be rolled up into a compact package. They do not have a
polarity. Capacitors with large values are usuallyelectrolytic.They have a polarity (or direction) and are sensitive to levels of voltage.
SI unit (symbol F) of electrical capacitance (how much electric charge acapacitorcan store for a given voltage). One farad is a capacitance of onecoulombper
volt. For practical purposes the microfarad (one millionth of a farad,
symbol mF) is more commonly used. The farad is named after English
scientist Michael Faraday.
Transistor A transistor is a semi-conductor
with the ability to amplify current. Transistors commonly consist of a tiny
sandwich of germanium or silicon, alternate layers having different electrical
properties because they are impregnated with minute amounts of different impurities.
A crystal of pure germanium or silicon would act as an insulator (non-conductor).
By introducing impurities in the form of atoms of other materials (for example,
boron, arsenic, or indium) in minute amounts, the layers may be made either
n-type, having an excess of electrons, or p-type, having a deficiency of electrons.
This enables electrons to flow from one layer to another in one direction
transistor has three terminals called the Emitter, Base and Collector.
When current flows into the base the emitter or the collector changes
the current to a higher level.
We use the transistors in this
robot to turn on the LED into a pulse form. We also use them to control
the rotating director of the left motor. The transistors amplify the
signal from the sensor to rotate the motor and could also be used to
cause the LED to flash.
Diodes The diodes used in this
circuit allow the flow of electrons one way only. This flow is from the anode
to the cathode. Therefore, diodes are basically a one-way valve for electrical
current. They let it flow in one direction (from positive to negative) and
not in the other direction. Most diodes are similar in appearance to
a resistor and will have a painted line on one end showing the direction or
flow (white side is negative). If the negative side is on the negative end
of the circuit, current will flow. If the negative is on the positive side
of the circuit no current will flow.
Microphone The microphone is used to pick
up the sound or vibration signal and convert it into an electrical signal.
It is a type of Field Effect Transistor (FET). The Sound Tracker robot uses
a condenser microphone as the sensor for detecting the sound of the robot
hitting an obstacle or the sound of your hands clapping.
Circuits, or ICs, are complex circuits inside one simple package. Silicon
and metals are used to simulate resistors, capacitors, transistors, etc. It
is a space saving miracle. These components come in a wide variety of packages
and sizes. You can tell them by their "monolithic shape" that has
a ton of "pins" coming out of them. Their applications are as varied
as their packages. It can be a simple timer, to a complex logic circuit, or
even a micro-controller (microprocessor with a few added functions) with erasable
memory built inside. The IC’s used in this robots amplifies the output voltage
from the sensor and these signals to the circuit controlling the left motor.
Basically it is amplifying the weak signals from the light sensor or phototransistor,
and sends them to the motors for controlling the robots movements.