Friday, 4 January 2013

Electronic Components & Parts & Their Function

Electronic-Components-and-Parts

Electronic Components & Parts & Their Function

Electronic components are basic electronic element or electronic parts usually packaged in a discrete form with two or more connecting leads or metallic pads.

Electronic Components are intended to be connected together, usually by soldering to a printed circuit board(PCB), to create an electronic circuit with a particular function (for example an amplifier, radio receiver, oscillator, wireless). Some of the main Electronic Components are: resistor, capacitor, transistor, diode, operational amplifier, resistor array, logic gate etc.

Electronic Components

Types of Electronic Components

Electronic Components are of 2 types: Active and Passive Electronic Components.

Passive electronic components are those that do not have gain or directionality. They are also called Electrical elements or electrical components. e.g. resistors, capacitors, diodes, Inductors.
Active components are those that have gain or directionality. e.g. transistors, integrated circuits or ICs, logic gate

Electronic Components and Their Functions

Terminals and Connectors: Components to make electrical connection.
Resistors: Components used to resist current.
Switches: Components that may be made to either conduct (closed) or not (open).
Capacitors: Components that store electrical charge in an electrical field.
Magnetic or Inductive Components: These are Electrical components that use magnetism.
Network Components: Components that use more than 1 type of Passive Component.
Piezoelectric devices, crystals, resonators: Passive components that use piezoelectric. effect. 8. Semiconductors: Electronic control components with no moving parts.
Diodes: Components that conduct electricity in only one direction.
Transistors: A semiconductor device capable of amplification.
Integrated Circuits or ICs: A microelectronic computer electronic circuitincorporated into a chip or semiconductor; a whole system rather than a single component

Q: transistor
R: resistor
RLA: RY: relay
SCR: silicon controlled rectifier
FET: field effect transistor
MOSFET: Metal oxide semiconductor field effect transistor
TFT: thin film transistor(display)
VLSI: very large scale integration
DSP: digital signal processor
SW: switch
T: transformer
TH: thermistor
TP: test point
Tr: transistor
U:integrated circuit
V: valve (tube)
VC: variable capacitor
VFD: vacuum fluorescent display
VR: variable resistor
X: crystal, ceramic resonator
XMER: transformer
XTAL: crystal
Z: zener diode

Electronic Components Abbreviations

Here is a list of Electronic Component name abbreviations widely used in the electronics industry:

AE: aerial, antenna
B: battery
BR: bridge rectifier
C: capacitor
CRT: cathode ray tube
D or CR: diode
F: fuse
GDT: gas discharge tube
IC: integrated circuit
J: wire link
JFET: junction gate field-effect transistor
L: inductor
LCD: Liquid crystal display
LDR: light dependent resistor
LED: light emitting diode
LS: speaker
M: motor
MCB: circuit breaker
Mic: microphone
Ne: neon lamp
OP: Operational Amplifier
PCB: printed circuit board
PU: pickup

Capacitor

Diode

Integrated Circuit (IC)

Inductors

Resistors

Transistors

Logic Gates

Electronic Companies (Manufacturers, Suppliers and Exporters):

Allied Electronics : List and details of all Actives and Passive Electronic Components.
Electronics Design World:Electronic components distributor Newark offers semiconductors, passives, interconnects, electromechanical, power source, specialty products, test and measurement equipment.
PartNumber.com - Free part utility to assign part numbers: An applet that assigns intelligent (significant) part numbers to components in electronic products.
Electronic Components Database - otxi.com: Online Technology Exchange, Inc.Electronic Component Distributor for Obsolete, Hard to Find, discontinued Integrated Circuits and Semiconductors. Providing an online parts search component database.
TOYO COMMUNICATION EQUIPMENT CO. LTD., Japan:Manufacturers and Suppliers of: Synthetic Quartz Crystals & Crystal Blanks, Microprocessor use/High Stability Ultra-Miniature & Surface Mount Type Crystals, HCM-Filters for Mobile/Cordless Telephones, Paging Receivers & other Communication Systems, SPXO / TCXO / DTCXO & OCXO Type Crystal Oscillators, Saw Devices upto 1-GHz
NIC COMPONENTS CORPORATION, U.S.A./Japan:Manufacturers and Suppliers of: Multi-Layer Ceramic Chip Capacitors, Chip Aluminum Electrolytic Capacitors, Chip Resistors/Resistor Networks, SMT Thermistors /Inductors / Varistors, Tantalum Chip Capacitors, Metallized Polyester Film Capacitor Chips, Leaded Miniature Electrolytic / Tantalum Capacitors, Ferrite Beads & Rectifier Diodes
RCD COMPONENTS, U.S.A. :Manufacturers and Suppliers of: Surface Mount Products, Chip Resistors, SIP-Networks & Active/Passive-Delay Lines, Resistor Network in Surface Mount, SIP/DIP packages, Wire-Wound Resistors, Resistance Standards, Carbon-Film, Metal Film & Metal Oxide Resistors, Special Purpose High Precision Resistors, Inductive Products/ Delay Lines, Surface Mount Ceramic Chip Capacitors, Surface Mount Tantalum Chip Capacitors
RARA ELECTRONICS CORPORATION, Korea:Manufacturers and Suppliers of: Wire Wound Resistors, Power Film Resistors, RF Resistors, Current Sensing Resistors, Precision Resistors, High Voltage Resistors
MEGAPHASE LLC, U.S.A. :Manufacturers and Suppliers of: TM Series Cables, VN Series Cables, Series 1 & 2 Cables, Series 3 & 5 Cables, Series 7 Cables, Jump Shot Coaxial Jumper Cables, 75-Ohm Site Line Test Cables, CM Series Test Cable, SF Series Test Cables, Site Line Field & Production Test Cable: SL Series, TM Series Bench Test Cables, Semi-Rigid Cable Assemblies, Micro-Miniature Semi-Rigid Cable Assemblies

Kirchhoff's Current Law

http://www.facstaff.bucknell.edu/mastascu/elessonshtml/basic/basic4ki.html

Kirchhoff's Current Law - Introduction
Kirchhoff's Current Law - KCL - is one of two fundamental laws in electrical engineering, the other being Kirchhoff's Voltage Law (KVL).

KCL is a fundamental law, as fundamental as Conservation of Mass in mechanics, for example, because KCL is really conservation of charge.
KVL and KCL are the starting point for analysis of any circuit.
KCL and KVL always hold and are usually the most useful piece of information you will have about a circuit after the circuit itself.
People and computer programs both use KVL and KCL for circuit analysis. Spice (in all its incarnations) starts with KCL.

Goals For This Lesson What should you be able to do after this lesson? Here's the basic objective.

   Given an electrical circuit:
   Be able to write KCL at every node in the circuit.
   Be able to solve the KCL equations, especially for simple circuits.

These goals are very important. If you can't write KCL equations and solve them, you may well be lost when you take a course in electronics in a few years. It will be much harder to learn that later, so be sure to learn it well now.

Kirchhoff's Current Law At this point, you have learned the fundamentals of charge and current. There is one important law, Kirchhoff's Current Law that you will need to learn. It is not as complex as it might seem. All you really need to know is that charge is conserved, so KCL is really based on one simple fact.

Charge can neither be created nor destroyed.

From that basic fact we can get to Kirchhoff's Current Law. Despite that simplicity, it is a fundamental, widely used law, that you need to know to go very far in electrical engineering. Let's examine a circuit simulation. It's shown below. Charge (current) is flowing through the circuit. The simulation shows some charge - the large red blob - flowing through a battery (where it picks up energy, but that's another story. Click here for that lesson.) That charge flows through Element #1 in the simulation. After the charge flows through Element #1 it splits. Some of the charge goes through Element #2, and some goes through Element #3. (Notice that it does not split equally! Sometimes it does. Sometimes it doesn't.) When, in the course of its flow through the circuit, there is no possibility of splitting, all of the charge entering a node will flow through the next element. (That element is said to be in series. Element #3 and Element #4 are in series because all of the current going through #3 goes through #4. Elements #1 and #2 are not in series.)
There is one node in the simulation where charge flowing through two elements comes together and "reunites" and flows back into the battery.

Note that this simulation emphasizes the conservation of charge. When charge flows through Element #1 when it gets to the end of Element #1 it splits into two. However, what arrives at that node is what leaves that node, so the amount of charge that enters the node - the big red blob - equals the amount of charge that leave that node - the sum of the charge on the medium sized red blob and the charge on the small red blob.

Problem1.  In this circuit, charge flows from the battery, through Element #1 to the node. Willy Nilly observes that 35 coulombs flows through Element #1 in 20 seconds, and that, in that same time, 17 coulombs flows through Element #2. How much charge flows through Element #3 in that time?
2.  How much charge flows through Element #4 in that time?
KCL        Charge usually flows through some sort of metallic wire, flowing through the atomic lattice. Although it is physically unlike water flowing in a pipe, that analogy is sometimes drawn. Like water confined to the interior of a pipe, charge is confined to flow within a wire, and it doesn't leave the surface of the wire. You may want to think in those terms as you interpret current flow in the sketches and diagrams that follow. We will be developing rules for current flow in circuits in this section. You will need to know about that in order to be able to analyze larger circuits with lots of elements.
        In practice current flows in wires and often splits between two or more devices. We need to consider what happens in networks of conductors in which current can split. Single wires carrying current aren't the most important case we can look at, and you need to learn about Kirchhoff's Current Law which describes those situations where we have large networks of interconnected elements carrying current. Those kinds of circuits will have many connection points (called nodes) where current can split into smaller currents. Shown below is part of a circuit. Current (I) comes in from the left and splits into two parts, I₁ and I₂. There is one simple relationship between these two currents and the current, I, flowing in from the left below.

Here, a red dot has been placed over both of the nodes in the picture.
Focus attention on a very short time, DT. Assume all currents constant during DT.

A current, I, flows into the top node, and I₁ and I₂ are flowing out of the node. No charge accumulates!
During time DT, the total amount of charge that flows into the node is zero so:

IDT - I₁DT - I₂DT = 0

And during DT,

IDT is the charge flowing in.
I₁DT is the charge flowing through the left resistor.
I₂DT is the charge flowing through the right resistor.

So, we have - for the period of time DT, the total amount of charge that flows into the node is zero so:

IDT - I₁DT - I₂DT = 0

Cancelling the DT's everywhere, we get:

I - I₁ - I₂ = 0

Which can be rephrased as:

The sum of the currents flowing into the node is zero.
or

I = I₁ + I₂

which says that "The current entering the node equals the current leaving the node."

We need to be more precise in this.

When we have the expression:

I - I₁ - I₂ = 0

Or when we think "The sum of the currents flowing into the node is zero."
We interpret I as a current entering and - I₁ and - I₂ also as currents entering. Note the negative signs!
Since I₁ is leaving the node, then we can think of - I₁ as the value of the current entering.
We do the same for I₂ and - I₂.

Again, we need to be more precise when we express things the other way.

When we have the expression:

I = I₁ + I₂ = 0

Or when we think "The sum of the currents flowing into the node equals the sum of the currents leaving the node."

We interpret I as a current entering and I₁ and I₂ as currents leaving.

Either of the above formulations is Kirchhoff's Current Law, otherwise known as KCL. If you understand that "The sum of the currents entering a node is zero.", then you know KCL. With that, it's time for you to answer a few questions.

Problems3. In this circuit - which you saw above - determine the current I₂, in terms of trhe other two currents. You will need to write KCL at the node marked with a red dot. Notice that we have defined current symbols and polarities for all the currents involved.

4. Now, determine a value for the current, I₂, when you have numerical values for the other currents.

I₁ = .75 A
I₃= - .45 A (nobody said the value had to be positive!)

5. Here is another circuit.

You need to determine a value for the current, I₄, given the following numerical values for some other currents. First, you'll need to get an algebraic expression for I₄. Click on the corrrect expression.

Now, determine the numerical value for I₄ when I₃ is 0.45A.
6. Here's a problem for you. In 10 seconds, an observer - Willy Nilly - notices that 35 coulombs of charge leaves node "n" in this circuit, heading for node "x". (Vn is the voltage at node "n", etc.) In the same ten seconds, 22 coulombs of charge leaves node "n" heading for node "z". Determine the current, I_y.

KCLThere are just a few points about Kirchhoff's Current Law that need to be made.

The complete expression of KCL is "The sum of all the currents entering a node is equal to the sum of all the currents leaving the node."
Kirchhoff's Current Law holds at every node in a network.
Kirchhoff's Current Law holds at every instant of time.

If you remember each of these items, you'll be able to figure out a great many things about circuits that you encounter. It's a very wide ranging and fundamental law in electrical engineering. We introduced this lesson with a simulation. That simulation seems to say a lot, and it really shows what KCL means. We'll let you look at it again.

Kirchhoff's Voltage Law

http://www.facstaff.bucknell.edu/mastascu/elessonshtml/basic/basic5kv.html

Kirchhoff's Voltage Law - Introduction
Kirchhoff's Voltage Law - KVL - is one of two fundamental laws in electrical engineering, the other being Kirchhoff's Current Law (KCL).

KVL is a fundamental law, as fundamental as Conservation of Energy in mechanics, for example, because KVL is really conservation of electrical energy.
KVL and KCL are the starting point for analysis of any circuit.
KCL and KVL always hold and are usually the most useful piece of information you will have about a circuit after the circuit itself.

Goals For This Lesson What should you be able to do after this lesson? Here's the basic objective.

Given an electrical circuit:
Be able to write KVL for every loop in the circuit.
Be able to solve the KVL equations, especially for simple circuits.

These goals are very important. If you can't write KVL equations and solve them, you may well be lost when you take a course in electronics in a few years. It will be much harder to learn that later, so be sure to learn it well now. (And, if you need to review the concept of voltage, here is a link to that lesson.

Kirchhoff's Voltage Law Here's a simple circuit. It has three components - a battery and two other components. Each of the three components will have a current going through it and a voltage across it. Here we want to focus on the voltage across each element, and how those three voltages are related.

We could measure voltage:

Anywhere along the wire shown in purple
Anywhere along the wire shown in green
Anywhere along the wire shown in blue.

Note: Any point along the green wire is at the same voltage, and the same situation pertains for the blue wire and the purple wire. Here's the same circuit. Here, with the button, you can move the dot representing charge around the circuit.

Answer these questions about what happens as that charge moves.

ProblemsQ1. As the charge moves from the top of the battery to the top of Element #1 (along the wire shown in purple), how much energy does the charge lose?

Q2. As the charge moves from the top of Element #1 through Element #1 to the bottom of element #1, how much energy does the charge lose?

Q3. As the charge moves from the bottom of Element #1 to the top of Element #2, how much energy does the charge lose?

Q4. As the charge moves from the top of Element #2 through Element #2 to the bottom of element #2, how much energy does the charge lose?

Q5. As the charge moves from the bottom of Element #2 to the bottom of the battery, how much energy does the charge lose?

Q6. As the charge moves from the bottom of the battery through the battery to the top of the battery, how much energy does the charge lose?

The last question is tricky because the charge actually gains energy as it goes through the battery. Now, we can track the energy acquired and given up by the charge as it traverses the circuit. And, as the charge completes one round trip around the circuit - returning to its starting point - there can be no net gain of energy or no net loss. That's really a statement of conservation of energy. What you put in is what you get out. TANSTAAFL! (There Ain't No Such Thing As A Free Lunch. It's not good English, but it says something that can't be said easily otherwise!) Let's formalize that.

The energy put into the charge as it goes through the battery is V_b * Q.
The charge loses V₁ * Q. as it goes through Element #1.
The charge loses V₂ * Q. as it goes through Element #2.
The net energy put into the charge (What's put in minus what it loses!) is:

V_b * Q - V₁ * Q - V₂ * Q = (V_b - V₁ - V₂)Q = 0

We can note that the amount of charge is irrelevant in what we have learned here. What we have learned is:

V_b - V₁ - V₂ = 0, or
V_b = V₁ + V₂ = 0

This can be paraphrased several ways:

Voltage across the battery = Voltage across Element #1 + Voltage across Element #2.
The algebraic sum of the voltages around a closed loop is zero.

There are some things to note about this conclusion - either way it is phrased. Note the following:

The conclusion does not depend on what the elements in the loop are. They can be anything at all but still, the algebraic sum of the voltages around a closed loop will be zero.
If you have a circuit with many loops, the algebraic sum of the voltages around any loop in the circuit is zero.

That last note will need a little explanation and work to be sure you understand it. Consider this circuit.

Q7. How many loops are there in the circuit above?

Writing The KVL Equations There is a good algorithm that can be stated for how to write the KVL equations for a loop. We'll need that when we examine this circuit again. Here's the statement of the algorithm.

Pick a starting point on the loop you want to write KVL for.
Imagine walking around the loop - clockwise or counterclockwise.
When you enter an element there will be a voltage defined across that element. One end will be positive and the other negative.
Pick the sign of the voltage definition on the end of the element that you enter. Conversely, you could choose the sign of the end you leave, except that you have to be consistent all the way around the loop.
Write down the voltage across the element using the sign you got in the previous step.
Keep doing that until you have gone completely around the loop returning to your starting point.
Set your result equal to zero.

Now let's do that for the loops in the circuit above.

A Comment Before we write the KVL equations, we need to notice something. The answer to Question #7 may not be correct. Let's think a little deeper to be sure we have it right. We took the correct answer to be two loops. In a sense that's correct, but in another sense there are three loops. In the picture below, each of the three buttons - when pressed - will show you one of the three loops. There's a loop there that you might not have thought about. Click the three buttons to see the three loops.

Now, let's write KVL for each of the three loops.

For the first loop (Battery, Element #1, Element #2)

-V_B + V₁ + V₂ = 0

For the second loop (Element #2, Element #3, Element #4). Note, you have to be careful with this one because you might not expect the voltage across Element #3 to be defined the way it is.

-V₂ - V₃ + V₄ = 0

For the third loop (Battery, Element #1, Element #3, Element #4)

-V_B + V₁ - V₃ + V₄ = 0

So, we get three equations - right? Actually, that's not right, because we do not get three independent equations. There are only two independent equations we can write.
That's not immediately obvious, so write the three equations as shown below. We'll put a horizontal line between the first two and the third equation.
-V_B + V₁ + V₂ = 0
-V₂ - V₃ + V₄ = 0

-V_B + V₁ - V₃ + V₄ = 0Can you see that you can add the first two equations to get the third? (Actually, there is a -V₂ and a +V₂, and those are the only things that cancel out when you add.) The third equation can be obtained from the first two equations, so it is not an independent equation. When you have the first two equations you can get the third from them!
What this means is that you have to be careful when you write KVL. You can write too many equations, and in being careful you might not write enough. Fortunately, if you look at a circuit you can almost always see how many independent loops there are by inspection. Going back to our question about how many loops there are in this circuit, the answer is that there are three loops but only two independent loops.
Now, let's see if you can apply your knowledge of KVL to solve a few simple problems.

ProblemsP1.  Using the same circuit you have been examining, answer the following questions. For the first problem if the battery is a 9v battery, and you know that V₁ = 3.7v, what is the value of V₂ (in volts)?
P2.   You also know that V₄ = 1.3v. What is the value of V₃ (in volts)?
P3.   Now, you have the voltages across all of the elements and the battery. Check your knowledge of KVL by putting your numbers into each of the three loop (KVL) equations for the circuit.

You're on your way to being a KVL expert. Try your hand on these problems, and you should be ready to move on to the next lesson.

ProblemsP4. Consider the case of two flashlight batteries. Inside a flashlight they are usually stacked something like the way they are shown below. There is also a voltmeter shown. It is connected to measure the voltage of the two batteries in series. Draw an equivalent circuit diagram that can be used to represent this situation. Compute the voltage that is measured by the voltmeter using KVL if each battery has 1.54v.
P5. Here is a circuit. Determine all of the loops in this circuit and write KVL for every loop.

P6. Here is a circuit. The voltage across element 1 is V1, etc. Write the KVL equations for the following loops:

V_in, and elements 1, 4, and 5.
V_in, and elements 1, 2, 6, and 7.
V_in, and elements 1, 2, 3, and 8.

P7. In the circuit below, write the KVL equations for:

The "center loop" with elements 5, 4, 2, 6, and 7;
The loop with elements 5, 4, 2, 3, and 8.

Show how these KVL equations can be derived from the KVL equations of Problem 3.

What If You Need More Than The KVL Equations? KVL gives a lot of information about a circuit. However, it doesn't give you everything you need to know all of the time. Sometimes you will need information from KCL - Kirchhoff's Current Law. You will also, always need the information that is contained in the descriptions of the elements themselves. For example, resistors have a relationship between the current flowing through the resistor and the voltage across the resistor. That information is crucial if there's a resistor in a circuit.
Still, without KVL you won't get very far analyzing circuits, so you will definitely use the information and concepts you learned in this lesson.

Cathode-Ray Oscilloscope

OBJECTIVE: To learn how to operate a cathode-ray oscilloscope.
APPARATUS: Cathode-ray oscilloscope, multimeter, and oscillator.
INTRODUCTION: The cathode-ray oscilloscope (CRO) is a common laboratory instrument that provides accurate time and aplitude measurements of voltage signals over a wide range of frequencies. Its reliability, stability, and ease of operation make it suitable as a general purpose laboratory instrument. The heart of the CRO is a cathode-ray tube shown schematically in Fig. 1.

          The cathode ray is a beam of electrons which are emitted by the heated cathode (negative electrode) and accelerated toward the fluorescent screen. The assembly of the cathode, intensity grid, focus grid, and accelerating anode (positive electrode) is called an electron gun. Its purpose is to generate the electron beam and control its intensity and focus. Between the electron gun and the fluorescent screen are two pair of metal plates - one oriented to provide horizontal deflection of the beam and one pair oriented ot give vertical deflection to the beam. These plates are thus referred to as the horizontal and vertical deflection plates. The combination of these two deflections allows the beam to reach any portion of the fluorescent screen. Wherever the electron beam hits the screen, the phosphor is excited and light is emitted from that point. This coversion of electron energy into light allows us to write with points or lines of light on an otherwise darkened screen.
          In the most common use of the oscilloscope the signal to be studied is first amplified and then applied to the vertical (deflection) plates to deflect the beam vertically and at the same time a voltage that increases linearly with time is applied to the horizontal (deflection) plates thus causing the beam to be deflected horizontally at a uniform (constant> rate. The signal applied to the verical plates is thus displayed on the screen as a function of time. The horizontal axis serves as a uniform time scale.
          The linear deflection or sweep of the beam horizontally is accomplished by use of a sweep generator that is incorporated in the oscilloscope circuitry. The voltage output of such a generator is that of a sawtooth wave as shown in Fig. 2. Application of one cycle of this voltage difference, which increases linearly with time, to the horizontal plates causes the beam to be deflected linearly with time across the tube face. When the voltage suddenly falls to zero, as at points (a) (b) (c), etc...., the end of each sweep - the beam flies back to its initial position. The horizontal deflection of the beam is repeated periodically, the frequency of this periodicity is adjustable by external controls.

          To obtain steady traces on the tube face, an internal number of cycles of the unknown signal that is applied to the vertical plates must be associated with each cycle of the sweep generator. Thus, with such a matching of synchronization of the two deflections, the pattern on the tube face repeats itself and hence appears to remain stationary. The persistance of vision in the human eye and of the glow of the fluorescent screen aids in producing a stationary pattern. In addition, the electron beam is cut off (blanked) during flyback so that the retrace sweep is not observed.
CRO Operation:  A simplified block diagram of a typical oscilloscope is shown in Fig. 3. In general, the instrument is operated in the following manner. The signal to be displayed is amplified by the vertical amplifier and applied to the verical deflection plates of the CRT. A portion of the signal in the vertical amplifier is applied to the sweep trigger as a triggering signal. The sweep trigger then generates a pulse coincident with a selected point in the cycle of the triggering signal. This pulse turns on the sweep generator, initiating the sawtooth wave form. The sawtooth wave is amplified by the horizontal amplifier and applied to the horizontal deflection plates. Usually, additional provisions signal are made for appliying an external triggering signal or utilizing the 60 Hz line for triggering. Also the sweep generator may be bypassed and an external signal applied directly to the horizontal amplifier.
CRO Controls
          The controls available on most oscilloscopes provide a wide range of operating conditions and thus make the instrument especially versatile. Since many of these controls are common to most oscilloscopes a brief description of them follows.

CATHODE-RAY TUBE
Power and Scale Illumination:  Turns instrument on and controls illumination of the graticule.
Focus:  Focus the spot or trace on the screen.
Intensity:  Regulates the brightness of the spot or trace.

VERTICAL AMPLIFIER SECTION
Position:  Controls vertical positioning of oscilloscope display.
Sensitivity:  Selects the sensitivity of the vertical amplifier in calibrated steps.
Variable Sensitivity:  Provides a continuous range of sensitivities between the calibrated steps. Normally the sensitivity is calibrated only when the variable knob is in the fully clockwise position.
AC-DC-GND:  Selects desired coupling (ac or dc) for incoming signal applied to vertical amplifier, or grounds the amplifier input. Selecting dc couples the input directly to the amplifier; selecting ac send the signal through a capacitor before going to the amplifier thus blocking any constant component.
HORIZONTAL-SWEEP SECTION
Sweep time/cm:  Selects desired sweep rate from calibrated steps or admits external signal to horizontal amplifier.
Sweep time/cm Variable:  Provides continuously variable sweep rates. Calibrated position is fully clockwise.
Position:  Controls horizontal position of trace on screen.
Horizontal Variable:  Controls the attenuation (reduction) of signal applied to horizontal aplifier through Ext. Horiz. connector.
TRIGGER
The trigger selects the timing of the beginning of the horizontal sweep.
Slope:  Selects whether triggering occurs on an increasing (+) or decreasing (-) portion of trigger signal.
Coupling:  Selects whether triggering occurs at a specific dc or ac level.
Source:  Selects the source of the triggering signal.
          INT - (internal) - from signal on vertical amplifier
          EXT - (external) - from an external signal inserted at the EXT. TRIG. INPUT.
          LINE - 60 cycle triger
Level:  Selects the voltage point on the triggering signal at which sweep is triggered. It also allows automatic (auto) triggering of allows sweep to run free (free run).
CONNECTIONS FOR THE OSCILLOSCOPE
Vertical Input:  A pair of jacks for connecting the signal under study to the Y (or vertical) amplifier. The lower jack is grounded to the case.
Horizontal Input:  A pair of jacks for connecting an external signal to the horizontal amplifier. The lower terminal is graounted to the case of the oscilloscope.
External Tigger Input:  Input connector for external trigger signal.
Cal. Out:  Provides amplitude calibrated square waves of 25 and 500 millivolts for use in calibrating the gain of the amplifiers.
          Accuracy of the vertical deflection is + 3%. Sensitivity is variable.
          Horizontal sweep should be accurate to within 3%. Range of sweep is variable.
Operating Instructions:  Before plugging the oscilloscope into a wall receptacle, set the controls as follows:
          (a) Power switch at off
          (b) Intensity fully counter clockwise
          (c) Vertical centering in the center of range
          (d) Horizontal centering in the center of range
          (e) Vertical at 0.2
          (f) Sweep times 1
Plug line cord into a standard ac wall recepticle (nominally 118 V). Turn power on. Do not advance the Intensity Control.
Allow the scope to warm up for approximately two minutes, then turn the Intensity Control until the beam is visible on the screen.

WARNING: Never advance the Intensity Control so far that an excessively bright spot appears. Bright spots imply burning of the screen. A sharp focused spot of high intensity (great brightness) should never be allowed to remain fixed in one position on the screen for any length of time as damage to the screen may occur.

Adjust Horizontal and Vertical Centering Controls. Adjust the focus to give a sharp trace. Set trigger to internal, level to auto.
PROCEDURE:
I. Set the signal generator to a frequency of 1000 cycles per second. Connect the output from the gererator to the vertical input of the oscilloscope. Establish a steady trace of this input signal on the scope. Adjust (play with) all of the scope and signal generator controls until you become familiar with the functionof each. The purpose fo such "playing" is to allow the student to become so familiar with the oscilloscope that it becomes an aid (tool) in making measurements in other experiments and not as a formidable obstacle. Note: If the vertical gain is set too low, it may not be possible to obtain a steady trace.
II. Measurements of Voltage: Consider the circuit in Fig. 4(a). The signal generator is used to produce a 1000 hertz sine wave. The AC voltmeter and the leads to the verticle input of the oscilloscope are connected across the generator's output. By adjusting the Horizontal Sweep time/cm and trigger, a steady trace of the sine wave may be displayed on the screen. The trace represents a plot of voltage vs. time, where the vertical deflection of the trace about the line of symmetry CD is proportional to the magnitude of the voltage at any instant of time.

          To determine the size of the voltage signal appearing at the output of terminals of the signal generator, an AC (Alternating Current) voltmeter is connected in parallel across these terminals (Fig. 4a). The AC voltmeter is designed to read the dc "effective value" of the voltage. This effective value is also known as the "Root Mean Square value" (RMS) value of the voltage.
          The peak or maximum voltage seen on the scope face (Fig. 4b) is V_m volts and is represented by the distance from the symmetry line CD to the maximum deflection. The relationship between the magnitude of the peak voltage displayed on the scope and the effective or RMS voltage (V_RMS) read on the AC voltmeter is
                    V_RMS = 0.707 V_m (for a sine or cosine wave).
Thus

          Agreement is expected between the voltage reading of the multimeter and that of the oscilloscope. For a symmetric wave (sine or cosine) the value of V_m may be taken as 1/2 the peak to peak signal V_pp
The variable sensitivity control a signal may be used to adjust the display to fill a concenient range of the scope face. In this position, the trace is no longer calibrated so that you can not just read the size of the signal by counting the number of divisions and multiplying by the scale factor. However, you can figure out what the new calibration is an use it as long as the variable control remains unchanged.
Caution:  The mathematical prescription given for RMS signals is valid only for sinusoidal signals. The meter will not indicate the correct voltage when used to measure non-sinusoidal signals.
III. Frequency Measurements:  When the horizontal sweep voltage is applied, voltage measurements can still be taken from the vertical deflection. Moreover, the signal is displayed as a function of time. If the time base (i.e. sweep) is calibrated, such measurements as pulse duration or signal period can be made. Frequencies can then be determined as reciprocal of the periods.
          Set the oscillator to 1000 Hz. Display the signal on the CRO and measure the period of the oscillations. Use the horizontal distance between two points such as C to D in Fig. 4b.
          Set the horizontal gain so that only one complete wave form is displayed.
          Then reset the horizontal until 5 waves are seen. Keep the time base control in a calibrated position. Measure the distance (and hence time) for 5 complete cycles and calculate the frequency from this measurement. Compare you result with the value determined above.
          Repeat your measurements for other frequencies of 150 Hz, 5 kHz, 50 kHz as set on the signal generator.
IV. Lissajous Figures:  When sine-wave signals of different frequencies are input to the horizontal and vertical amplifiers a stationary pattern is formed on the CRT when the ratio of the two frequencies is an intergral fraction such as 1/2, 2/3, 4/3, 1/5, etc. These stationary patterns are known as Lissajous figures and can be used for comparison measurement of frequencies.
          Use two oscillators to generate some simple Lissajous figures like those shown in Fig. 5. You will find it difficult to maintain the Lissajous figures in a fixed configuration because the two oscillators are not phase and frequency locked. Their frequencies and phase drift slowly causing the two different signals to change slightly with respect to each other.
V. Testing what you have learned:  Your instructor will provide you with a small oscillator circuit. Examine the input to the circuit and output of the circuit using your oscilloscope. Measure such quantities as the voltage and frequence of the signals. Specify if they are sinusoidal or of some other wave character. If square wave, measure the frequency of the wave. Also, for square waves, measure the on time (when the voltage is high) and off time (when it is low).

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Friday, 4 January 2013

Electronic Components & Parts & Their Function

http://the-engineer.hubpages.com/hub/Electronic-Components-and-Parts

Electronic Components & Parts & Their Function

Types of Electronic Components

Electronic Components and Their Functions

Q: transistor

R: resistor

RLA: RY: relay

SCR: silicon controlled rectifier

FET: field effect transistor

MOSFET: Metal oxide semiconductor field effect transistor

TFT: thin film transistor(display)

VLSI: very large scale integration

DSP: digital signal processor

SW: switch

T: transformer

TH: thermistor

TP: test point

Tr: transistor

U:integrated circuit

V: valve (tube)

VC: variable capacitor

VFD: vacuum fluorescent display

VR: variable resistor

X: crystal, ceramic resonator

XMER: transformer

XTAL: crystal

Z: zener diode

Electronic Components Abbreviations

AE: aerial, antenna

B: battery

BR: bridge rectifier

C: capacitor

CRT: cathode ray tube

D or CR: diode

F: fuse

GDT: gas discharge tube

IC: integrated circuit

J: wire link

JFET: junction gate field-effect transistor

L: inductor

LCD: Liquid crystal display

LDR: light dependent resistor

LED: light emitting diode

LS: speaker

M: motor

MCB: circuit breaker

Mic: microphone

Ne: neon lamp

OP: Operational Amplifier

PCB: printed circuit board

PU: pickup

Electronic Companies (Manufacturers, Suppliers and Exporters):

Kirchhoff's Current Law

Kirchhoff's Voltage Law

Cathode-Ray Oscilloscope

Cathode-Ray Oscilloscope