HELE / TLEelectronics

LESSON 3 - Schematic Symbols of Electronics Components

COMPONENT/PART

SYMBOL ACTUAL

1.RESISTOR

a. fixed resistor

b. potentiometer or volume control

c. variable resistor

2. CAPACITOR

a. fixed capacitor (non-polarized)

b. electrolyte filter capacitor (polarized)

COMPONENT/PART SYMBOL ACTUAL

c. variable capacitor (gang tuning)

d. trimmer

3. SEMICONDUCTOR a. rectifier diodes

b. light emitting diode (LED)

c. Zener diode

d. bridge diode

4. LOUDSPEAKER

COMPONENT/PART SYMBOL ACTUAL

5. TRANSISTORS

a. PNP transistor

b. NPN transistor

6. PLUG

7. WIRINGS

a. wires connected

b. wires not connected

COMPONENT/PART SYMBOL ACTUAL

8. GROUND

9. SWITCHES

a. single pole single throw (SPST)

b. double pole double throw (DPDT)

c. push button normally closed

d. push button normally open

e. rotary or selector slide switch

COMPONENT/PART SYMBOL ACTUAL

f. slide switch

10. AC TRANSFORMERS

a. step-down

b. variable output voltage

c. inductor

d. coil

11.FUSE

12. PILOT LIGHT OR LAMP

LESSON 4 – Diagram used in

Electronics

Block or circuit Diagram- shows only the complete connections and interconnections of

the components as well as the flow or process in a circuit.

Pictorial or Schematic Diagram- shows a more detailed description of the components. It helps

identify exactly where the components are installed for easy troubleshooting.

RESISTOR COLOR CODING- color coded resistance value- 4 color bands

- 1st 3 color is the resistance- 4th color represent the tolerance

LESSON 5 – Color Coding of Resistors and Capacitors

1st significant digit

2nd significant digit

Represents the number of zeroes (MULTIPLIER)

TOLERANCE

BLACK 0 0 0 -

BROWN 1 1 1 + 1%

RED 2 2 2 + 2%

ORANGE 3 3 3 + 3%

YELLOW 4 4 4 + 4%

GREEN 5 5 5 -

BLUE 6 6 6 -

VIOLET 7 7 7 -

GRAY 8 8 8 -

WHITE 9 9 9 -

GOLD - - Decimal point is after the first

significant digit

+ 5 %

SILVER - - Decimal point is before the first significant digit

+ 10 %

NONE + 20%

Capacitor- can store electrical charges or voltages- the amount of electrical charge that

can store --- “Farad”- FARAD (F)

- very large unit of capacitance- can also be expressed in

“millifarad”(mF), “microfarad” (mF), “nanofarad” (nF), and “picafarad” (pF)

PREFIX SYMBOL

SCIENTIFIC

NOTATION

MATHEMATICAL EQUIVALENT

Milli m 103 0.0001

Micro µ or u 106 0.000 001

Nano Ωn 109 0.000 000 001

Pico p 10-12 0.000.000 000 001

COLOR MULTIPLIER VOLTAGEBlack 1 microFarad 10Brown 10 microFarad

Red 100 microFarad

Yellow 6.3Green 16Blue 20

VioletGray 0.01

microFarad25

White .1 microFarad 3Pink 35

Volt-Ohm-Milliammeter (V.O.M)- is a device with 3 different testers

contained in one case.- V.O.M is used for measuring

resistance, measuring AC voltage, measuring DC voltage, and for measuring current

LESSON 6 – Uses of the Multi-tester or Volt-Ohm-Milliammeter

(V.O.M)

LEGEND:1. Indicator zero

corrector2. Range selector

switch knob3. Measuring terminal

+4. Measuring terminal

– COM (common)5. OUTPUT

(series condenser)

6. 0Ω adjusting knob

7. Panel8. Indicator pointer10. Rear case

10 8

15 6

7 2

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Ohmmeter- this is the topmost scale of the multimeter

which is used to measure resistance and to test component -- such as diodes, capacitors, transistors and coils

TWO IMPORTANT FACTORS TO BE DONE BEFORE TAKING RESISTANCE MEASUREMENTS

1. Select a proper range or multiplier in the function selection.

2. Adjust the needle or the points to zero reading. This is done by shorting together the two test prods and turning the ohms adjustment knob slowly until the needle points

Voltmeter - a device used to measure AC and

DC voltages

- has 3 sets of scales: scale is 0-10 V if the voltage is less

than 10 volts: 0-50 V when expected voltage is 50: 0-250 V if the expected voltage is

250

Milliammeter - used to measure small current flowing in a given circuit

component

Measuring Procedurea. Adjustment of meter to zero position

- turn the zero position adjusterb. Range Selection

- select proper range for the item to be measured

- set first the range selector knob to the highest level to avoid damage on the meter

A. Measuring DCV1. set the range selector knob on appropriate

DCV range2. Apply the black test pin to the minus

potential of measurement circuit and the red test pin to the plus potential

3. Read the movement of the pointer by V and A scale

B. Measuring ACV1. turn the range selector knob to an

appropriate ACV range2. Apply the test leads to measured circuit3. Read the movement of pointer V and A scale

C. Measuring DCA1. Turn the range selector knob to an appropriate

DCA range2. Take out measured circuit and apply the black test

pin to the minus potential of measured circuit and red test pin to the plus potential. Observe circuit polarity.

3. Read the movement of the pointer by V and A scale.

Note: Connect the meter in series with a load

D. Measuring Resistance1. Turn the range selector knob to an appropriate

resistance range2. Short the red and black test pins and turn the zero

ohm adjuster so that the pointer may align exactly to zero ohm.

Note: If the pointer fails to swing up to 0 even when the 0 adjuster is turned full clockwise, the battery maybe defective

A simple electronic project will be easy to construct if the following hints are followed:

working area should be well –ventilated and away from children

Read thoroughly the entire construction procedure first and always refer to your diagram

Observe safety rules and practices in doing your work

Buy only original or high quality components

LESSON 7 – Constructing a Simple Electronic Project

Some choices you can select from in constructing a simple electronic project:

HALF WAVE POWER SUPPLY

FULL WAVE POWER SUPPLY

FULL WAVE BRIDGE TYPE POWER SUPPLY

DC OUTPUT POWER SUPPLY