Post on 15-Jan-2016
transcript
ELECTRONIC CIRCUITS FOR GRADE 9
Prepared by G. C. Accom
SOME OF THE SYMBOLS WE WILL USE
SYMBOL NAME SYMBOL NAME SWITCH LDR
BULB
RESISTOR
TRANSISTOR
CAPACITOR
BUZZER DIODE
CELLS IN PARALLEL
CELLS IN SERIES
How to make a simple cell-holder for batteries
USE A PIECE OF RUBBER
HOSE AND A KNIFE
CUT A SLIT INTO THE HOSE
SLIDE THE NUMBER OF CELLS YOU NEED INTO THE SLIT YOU HAVE CUT
I GRADE 9 YOU WILL BE WORKING WITH THE FOLLOWING POWER SOURCES
EXPLAIN TO LEARNERS
WHY WE SAY THESE CELLS
ARE CONNECTED
IN SERIES
A SIMPLE CIRCUIT WITH CELLS CONNECTED IN SERIES
PUSH SWITCHALWAYS ON
SWITCH MADE WITH PAPER CLIP AND THUMB TACK
TOGGLE SWITCH
PUSH SWITCH ALWAYS OFF
PUSH SWITCH Normally ON in its normal state
It switches OFF when you press it
PUSH SWITCH Normally OFF in its normal state
It switches ON when you press it
CIRCUIT DIAGRAM FOR TWO CELLS CONNECTED IN SERIES
SWITCH OPEN
SWITCH CLOSED
CELLS CONNECTED IN PARALLELSwitch Open
CELLS CONNECTED IN PARALLELSwitch Closed
BULBS CONNECTED IN SERIES
SEE WHAT HAPPENS WHEN ONE BULB IS REMOVED
BULBS CONNECTED IN PARALLEL
SEE WHAT HAPPENS WHEN ONE BULB IS REMOVED
AND SWITCH – Both Open
AND SWITCH – One Closed
AND SWITCH – Both Closed
OR SWITCH – Both Open
OR SWITCH – Bottom switch closed
OR SWITCH – Top switch closed
OR SWITCH – Both switches closed
4,5 v battery, switch, resistor and LED
CIRCUIT DIAGRAM
LDR, buzzer, 3v battery
Buzzer sounds when light of torch is brought close
CIRCUIT DIAGRAM
LDR with LED
LED is ON in absence of LIGHT
LED is OFF in presence of LIGHT
CIRCUIT DIAGRAM
Circuit with switch, resistor, capacitor, diode & LED
NOTE- LED is OFF
NOTE- LED is ON
NOTE POWER SUPPLY IS REMOVED BUT - LED is still ON
CIRCUIT DIAGRAM
TOUCH OR MOIST DETECTORSWITCH OPEN = LED OFF
WATER
SWITCH CLOSED = LED ON
WATER
CIRCUIT DIAGRAM
YOU CAN USE EXACTLY THE SAME CIRCUIT TO ADD A BUZZER
WATER
CONNECT TERMINALS OF BUZZER HERE