1. ELECTRONIC CIRCUITS FOR GRADE 9 Prepared by G. C. Accom

2. SOME OF THE SYMBOLS WE WILL USE

3. How to make a simple cell-holder for batteries USE A PIECE OF RUBBER HOSE AND A KNIFE

4. CUT A SLIT INTO THE HOSE

5. SLIDE THE NUMBER OF CELLS YOU NEED INTO THE SLIT YOU HAVE CUT

7. I GRADE 9 YOU WILL BE WORKING WITH THE FOLLOWING POWER SOURCES EXPLAIN TO LEARNERS WHY WE SAY THESE CELLS ARE CONNECTED IN SERIES

8. A SIMPLE CIRCUIT WITH CELLS CONNECTED IN SERIES PUSH SWITCH ALWAYS ON SWITCH MADE WITH PAPER CLIP AND THUMB TACK TOGGLE SWITCH PUSH SWITCH ALWAYS OFF

9. PUSH SWITCH Normally ON in its normal state

10. It switches OFF when you press it

11. PUSH SWITCH Normally OFF in its normal state

12. It switches ON when you press it

14. CIRCUIT DIAGRAM FOR TWO CELLS CONNECTED IN SERIES

15. SWITCH OPEN

17. SWITCH CLOSED

18. CELLS CONNECTED IN PARALLEL Switch Open

20. CELLS CONNECTED IN PARALLEL Switch Closed

21. BULBS CONNECTED IN SERIES

23. SEE WHAT HAPPENS WHEN ONE BULB IS REMOVED

24. BULBS CONNECTED IN PARALLEL

26. SEE WHAT HAPPENS WHEN ONE BULB IS REMOVED

27. AND SWITCH – Both Open

28. AND SWITCH – One Closed

29. AND SWITCH – Both Closed

30. OR SWITCH – Both Open

31. OR SWITCH – Bottom switch closed

32. OR SWITCH – Top switch closed

33. OR SWITCH – Both switches closed

35. 4,5 v battery, switch, resistor and LED

36. CIRCUIT DIAGRAM

37. LDR, buzzer, 3v battery

38. Buzzer sounds when light of torch is brought close

39. CIRCUIT DIAGRAM

40. LDR with LED

41. LED is ON in absence of LIGHT

42. LED is OFF in presence of LIGHT

43. CIRCUIT DIAGRAM

44. Circuit with switch, resistor, capacitor, diode & LED NOTE- LED is OFF

45. NOTE- LED is ON

46. NOTE POWER SUPPLY IS REMOVED BUT - LED is still ON

47. CIRCUIT DIAGRAM

48. TOUCH OR MOIST DETECTOR SWITCH OPEN = LED OFF WATER

49. SWITCH CLOSED = LED ON WATER

50. CIRCUIT DIAGRAM

51. YOU CAN USE EXACTLY THE SAME CIRCUIT TO ADD A BUZZER WATER CONNECT TERMINALS OF BUZZER HERE