Electronic Circuits
Lectures: Prof. dr hab. inż. Wojciech Kucewicz
Project and Laboratory:
MSc. Piotr Dorosz, Eng.
Department of Electronics AGH,
Bulding nr C2, room 409
email: pdorosz@agh.edu.pl
Classes: 2 academic hours a week
(28 hours in semester).
From the beginning of electronics (Ohm’s law, Kirchhoff’s rule)
Through electronics devices (semiconductor, diode, bipolar transistor,
unipolar transistor)
Ending with integrated circuits used in practical applications
(automotive in particular).
What will be required of you:
Active participation and reports (finishing the exercices during classes,
your own initiative),
Tests (twice in the semester) about topics appearing during laboratories
and lectures.
Grade from the final project (topics will be given in the middle of the
semester).
THE END RESULT – completing the course
Electronics deals with electrical circuits that involve active electrical
components such as vacuum tubes, transistors, diodes and integrated
circuits, and associated passive interconnection technologies. The
nonlinear behaviour of active components and their ability to control
electron flows makes amplification of weak signals possible and
electronics is widely used in information processing,
telecommunications, and signal processing. The ability of electronic
devices to act as switches makes digital information processing possible.
Interconnection technologies such as circuit boards, electronics
packaging technology, and other varied forms of communication
infrastructure complete circuit functionality and transform the mixed
components into a regular working system.
General distinction:
-analog electronic circuits
-digital electronic circuits.
Analogue electronics (or analog in American English) are electronic
systems with a continuously variable signal, in contrast to digital
electronics where signals usually take only two different levels. The term
"analogue" describes the proportional relationship between a signal and a
voltage or current that represents the signal. The word analogue is
derived from the Greek word ανάλογος (analogos) meaning
"proportional„
Digital electronics, or digital (electronic) circuits, represent signals by
discrete bands of analog levels, rather than by a continuous range. All
levels within a band represent the same signal state. Relatively small
changes to the analog signal levels due to manufacturing tolerance,
signal attenuation or parasitic noise do not leave the discrete envelope,
and as a result are ignored by signal state sensing circuitry.
[source: WIKIPEDIA)
An analog or analogue signal is any continuous signal for which the
time varying feature (variable) of the signal is a representation of some
other time varying quantity, i.e., analogous to another time varying
signal. An analog signal has a theoretically infinite resolution.
Digital electronics, or digital (electronic) circuits, represent signals by
discrete bands of analog levels, rather than by a continuous range. All
levels within a band represent the same signal state. In most cases the
number of these states is two, and they are represented by two voltage
bands: one near a reference value (typically termed as "ground" or zero
volts) and a value near the supply voltage, corresponding to the "false"
("0") and "true" ("1") values of the Boolean domain respectively.
[source: WIKIPEDIA]
Design Tool
MULTISIM: electronic circuits simulator.
It allows to:
Check how the circuit built from virtual elements works,
without the need of physically creating the circuit itself.
Free version of the program can be downloaded from:
http://www.ni.com/multisim/
układy cyfrowe
źródła
diody
podstawowe
elementy
układy analogowe
tranzystory
Toolbar-elements of electronic and electrical systems
przyrząd pomiarowy
generator
oscyloskop
Measurement devices
and analyzers menu
Basic Electrical Quantities:
-current,
-voltage,
-electrical resistance,
-capacity.
Basic Passive Elements:
-resistor,
-capacitor,
-potentiometer.
Basic Electronics Laws:
-Ohm’s law,
-Kirchhoff’s law.
They are the key issues in understanding what is
going on during these classes!!!
Electric current intensity- I (called electric current), it is a physical
quantity characterizing the flow of current. It is defined as the ratio
between the electric load vaule flowing through defined surface and the
time of the flow:
Ampere – electric current intensity unit. It is the base unit in both SI and
MKSA systems of unit, marked with A symbol.
Electric voltage– difference of electric potentials between two points of
an electric circuit or electric field. The symbol of voltage is U. Voltage is
equal to the work done per unit charge against a static electric field to
move the charge between two points.
The volt (symbol: V) is the SI derived unit for electric potential
(voltage), electric potential difference, and electromotive force. A single
volt is defined as the difference in electric potential across a wire when
an electric current of one ampere dissipates one watt of power.
Additionally, it is the potential difference between two points that will
impart one joule of energy per coulomb of charge that passes through it.
Electrical resistance (R symbol) – a quantity characterizing the relations
between voltage and electric current intensity in the circuits of direct
current (DC). In alternating current (AC) circuits electrical resistance is
the real part of complex impedance. The unit of resistance in SI is an
Ohm (Ω).
U=RI
Electrical capacitance of the secluded conductor is a physical quantity
C equal to the ratio between load q accumulated on the conductor and the
electrical potential of that conductor.
1 Farad (F) – the unit of electrical capacitance in SI (SI derived unit)
This is the capacitance of the electrical conductor, the potential of which
is increased by 1 volt after 1 Coulomb load delivery.
A resistor is a passive two-terminal electrical component that
implements electrical resistance as a circuit element. The ratio of the
voltage applied across a resistor's terminals to the intensity of current in
the circuit is called its resistance, and this can be assumed to be a
constant (independent of the voltage) for ordinary resistors working
within their ratings. It is a linear element i.e. voltage drop over it is
proportional to the current flowing through it. Practical resistors have a
series inductance and a small parallel capacitance.
Capacitor is an electrical element built with two conductors (electrodes)
separated by dielectric. Voltage supplied to the capacitor electrodes
causes the assembly of the electric charge. After disconnecting the power
supply, load remains on the electrodes because of the electrostatic forces.
If the capacitor as a whole is not electrified then the charge accumulated
on both covers is equal in value but of opposite sign. The capacitor has a
capacitance C determining the ability of the capacitor to accumulate the
charge.
A potentiometer, informally a pot, is a three-terminal resistor with a
sliding contact that forms an adjustable voltage divider. If only two
terminals are used, one end and the wiper, it acts as a variable resistor or
rheostat.
A potentiometer measuring instrument is essentially a voltage divider
used for measuring electric potential (voltage); the component is an
implementation of the same principle, hence its name.
Potentiometers are commonly used to control electrical devices such as
volume controls on audio equipment. Potentiometers operated by a
mechanism can be used as position transducers, for example, in a
joystick. Potentiometers are rarely used to directly control significant
power (more than a watt), since the power dissipated in the
potentiometer would be comparable to the power in the controlled load.
Ohm’s Law
Georg Simon Ohm was a German physicist and mathematician. He
discovered the relationship in 1825-1826.
Ohm's law states that the current through a conductor between two points
is directly proportional to the potential difference across the two points.
U
R
I
„Checking” OHM’S LAW using MULTISIM
Stage 1- „placing” voltage
controlled voltage source.
1. Wybierz
źródła
3. Połóż
element
2. Wybierz
źródło
napięcia
sterowane
napięciem
The result
Stage 2. „placing” voltage source
Result
Build the circuit!!!
Start the simulation
Current measurement (click twice on multimeter 1
with LMB – Left Mouse Button)
Voltage measurement on the resistance
Changing the voltage on voltage source in
the circuit with the test 1kOhm resistor – click
twice LMB
Setting the potentiometer on 40%, the results of voltage and current
measured (U to I ratio stays constant!!!)
Check voltage and current for different settings of the potentiometer
Function generator: electronic device used for generating electrical
signals of different shape:
-sinusoidal,
-rectangle,
-triangle.
Setting the generator
(LMB click twice)
Oscilloscope - is a type of electronic test instrument that allows
observation of constantly varying electrical signals, usually as a twodimensional graph.
Oscilloscope – settings
(LMB click twice)
Connecting the devices
Simulation – functional generator connected to the oscilloscope
A light-emitting diode (LED) is a semiconductor
light source. Appearing as practical electronic
components in 1962, early LEDs emitted low-intensity
red light, but modern versions are available across the
visible, ultraviolet, and infrared wavelengths, with
very high brightness.
Build the circuit
Run the simulation
Setting the frequency of the generator enables to change the period of
częstotliwości generatora pozwala na zmianę okresu of lighting and
extinguishing the LED.
Coming up next
week!!!
Kirchhoff’s Laws
Kirchhoff's first law – At any node (junction) in an electrical circuit, the
sum of currents flowing into that node is equal to the sum of currents
flowing out of that node, or:
The algebraic sum of currents in a network of conductors meeting at a
point is zero.
Kirchhoff's second law– also called voltage law, applies to the balance
of voltage in the closed circuit.
In the closed circuit voltage drops on the total resistance is the sum of
electromotive forces present in the circuit.