common components

8/10/2019 Common Components

1/4

Symbol/ Picture Description/ Circuit

The resistance of the LDRdecreases as the lightlevel increases.

Relay on when darkThe relay is energised whenthe light level increases abovethe level set by 220R variableresistor.

R1N4148

+9V

1K

220R

NORPS12LDR

0V

12V RelayMin 100Rcoil resistance60-4465

BFY51or

BC639

LDR

Thermistors With negative temperaturecoefficient (NTC) typethermistors as the temperatureincreases, the resistance of thethermistor decreases and theoutput voltage increases.

When switches are connectedin series the LED will light onlywhen all the switches arepushed simultaneously.

Connecting switches in parallelmean that when either switch ispressed the LED will light.

Motor reversing circuit using aDouble pole Double throwswitch.

Circuit diagram for keypad.

A simple amplification circuit fora microphone insert.

Electret microphones need aload resistor to work theinternal amplifier.

-to

+Vcc

-Vcc

Vout

Switches

+

-

+

-

+

-

+

+

-

-

Single poleSingle throw

Push tomake

Push tobreak

Single poleDouble throw

Double poleDouble throw

Microphoneinsert

Keypad

1 2 3

4 5 6

7 8 9

* 0 #

NO

Microphone +v 9v

0v

NORPS12

Input

Common components

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2/4


Flat side =negativeLED

a

b

c

d

e

f

g

DP

a

b

c

d

e

f

g

DP

7 Segment Displays

LEDs are cheap, low powerdevices that convertelectrical energy into light.A protective resistor isneeded when connecting to

a battery or power supply.

4026Note: Connect currentlimiting resistors betweeneach decoder output andthe segment of the display.

DescriptionIn the circuit the 4026 isdriving a common cathodeseven-segment display.

Each time a pulse is fedinto the input of thecounter, the output isincreased by one digit. The counter can be reset by taking R (pin 15) high.Taking STR (pin 2) high will halt the count. The divide by ten out provides anoutput pulse every tenth input pulse and can be used to drive the nextcounter to display larger numbers.

Relays A diode must be used toprotect a transistor whenusing a relay. When thecurrent is removed fromthe coil of the relay avoltage is induced in thecoil. The diode is used

across the coil to preventthe voltage from damagingthe transistor.

Resist or Values for LEDsSuggested values for resistors when usingLEDs with batteries orpower supplies.

Voltage Value

3V 1205V 2209V 47012V 560

3

2

1

158

16

5

4

4026

DE

R Vss

Vdd

CLKC

abc

defg

DO

c'STR

V-

g

f

e

a

d

b

c

dp

56K

+9V

0V

Push-to-makeswitchRESET

INPUT

10

OUT

76119

131210

Commoncathode

display

R

IF

+VS

R =VS -VLEDIF

Switch connections

Switch contacts

Coil connections

Soft arm armaturePivot

Coil

Soft iron core

Motor There are a number ofdedicated ICs that canbe used to drivestepper motors. Theselection dependsupon the motor usedand the control

required.

E1

IN 1

OUT 1

GND

GND

OUT 2

IN 2

VC

VS

IN 4

OUT 4

GND

GND

OUT 3

IN 3

E2+9V

+5V

+5V

+5V

L293D PIC16F84

RB0

RB1

RB2

RB3

37-0525Bi polar stepper motor

AABB

+9V

0V

BC639/BFY51Transistor

RELAYDiodeIN4148

1K

ResistorINPUT

Speaker

Piezo

55 5

ASTABLE

Piezo buzzer

3

+9VPiezo Bu zzerUse a high speed astablecircuit to drive a piezosounder.

Common Anode

Anode Cathode

(Cathode)

Common Cathode

The speaker is the finalsection of the translationcircuit. It takes the electricalsignal and translates it backinto physical vibrations tocreate sound waves.The speaker should producethe same vibrations that themicrophone originallyrecorded and encoded.

RLY

DC Motor

Steppermotor circuit

Output


3/4


Transistor

Semiconduc

torsDiscrete

PNP

NPN

b

c

e

Darlingt on Pair

a

g

c

Thyristor Thyristor ( SCR)When a voltage is appliedto the gate of the thyristor(SCR) it turns on. When thevoltage to the gate isremoved the thyristor willconduct until the power isremoved by shortingbetween the anode andcathode.

cb

ec

b

e

cb

e

Type of Order Case IC (max) Vce HFE Power Applicat iont ransist or code mA (max)V (min) mWBC178 81-0028 TO-18 200 25 120 600 GeneralBC327 81-0050 TO-92(C) 800 45 100 625 General

Common PNP transistor information

Type of Order Case IC (max) Vce HFE Power Applicat iont ransist or code mA (max)V (min) mW

TIP120 81-0168 TO-220 5000 60 1000 65000 GeneralBCX38B 81-0084 E-LINE 800 60 2000 1000 General

Darlington pair

Common NPN transistor informationType of Order Case IC (max) Vce HFE Power Applicat iont ransist or code mA (max)V (min) mWBC108 81-0014 TO-18 200 25 100 600 GeneralBC548B 81-0066 TO-92(C) 100 30 180 500 GeneralBFY51 81-0122 TO-39 1000 30 40 800 GeneralBC639 81-0080 TO-92(A) 1000 80 150 800 General

+9V

0V

ON

OFF

LED

470R

1K

Thyristor

BC108

BC178

TIP120 BCX38B

2N5060 TIC106D

BC327

BC548B BFY51 BC639

Darlington PairTransistor Switch

Resistors

0Black 0

9 9

Brown

Red 00

Orange 000

Yellow 0000

Green

Blue 000000

Violet

Grey

White

2 2

3 3

4 4

5 5

6 6

8 8

1 1

Gold 10 5% tolerance

1% tolerance0

7 7 0000000

00000

1K (1000) 5%

4R7 (4.7) 5%

1M5 (1,500,000) 5%

EXAMPLES

220K(220,000) 5%

Fixed

Preset

Potentiometer

Rapid Electronics Limited

Severalls Lane, Colchester, Essex CO4 5JS

Telephone: 01206 751166 Fax: 01206 751188

E-mail: [email protected]

Website: www.rapidonline.com

Process


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1

2

3

4 5

6

7

8 Vcc

Discharge

Threshold

Control Voltage

GND

Trigger

Output

Reset

NE555

1

2

3

4 5

6

7

8 NC

+V

Output

Offset Null

Off set Null

Inverting Input

Non-inverting input

-V

741

The timer can be either monostable or astable mode.

MonostableA circuit has one stablestate. When triggered it willreturn to that stable state.The timing period can bealtered by changing thevalues of the resistor andthe capacitor in the timingsection of the circuit.

AstableA circuit that has no stablestate. It will continuallyalternate from one state tothe other.To alter the frequency ofthe astable multivibratorcircuit change the valuesof resistance andcapacitance in the timingsection of the circuit.

55 5

GND

Vcc

DIS

THR

TR

CV

OP

RST

1 5

2

7

6

470R

3

84

0V

+9V

INPUT TIMING CONTROL OUTPUT

Push-to-makeswitch

55 5

GND

VccDIS

THR

TR CV

OP

RST

+ 1 52

7

6

470R

3

84

0V

+9V

TIMING CONTROL OUTPUT

When the thermistor iswarm and above the settemperature, the outputwill be negative.When the thermistor iscool and below the settemperature, the outputwill be positive.

Negative feedbackenables greater controlover the amplification ofthe operational amplifier.

INPUT PROCESS OUTPUT

0V

+9V

-9V

76

4

2

3

74 1

Thermistor5K at 25 C

5K6

10K

5K6 5K6

LED

390R

OPERATIONAL AMPLIFIER

AS A COMPARATOR

0V

76

4

2

3

74 1

Rf+Vcc

-Vcc

Ri

Inverting amplifier

VoutVin

Gain =Rf

RI

SemiconductorsICs

+-

Capacitors Capacitance Capacitance Capacitance Capacitance(Picofarad PF) (Nanofarad NF) (M icrofarad F) Code

10 0.01 10015 0.015 15047 0.047 47082 0.082 820100 0.1 101330 0.33 331470 0.47 0.00047 4711000 1.0 0.001 1021500 1.5 0.0015 1522200 2.2 0.0022 2224700 4.7 0.0047 4726800 6.8 0.0068 68210000 10 0.01 10322000 22 0.022 22347000 47 0.047 473100000 100 0.1 104220000 220 0.22 224

470000 470 0.47 474

Total of capacitors in series 1 =1 +1 +1

Total of capacitors in parallel CT =C1 +C2 +C3 ...etc

CT C1 C2 C3 ...etc

First two digitssignificant figures -third digit isnumber of zeros

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