4. WORKSHOP PRACTICE
WEEK-5

5. OBJECTIVE OF LAB-5
Introduction to digital multimeter and its measuring method.
To be familiar with the connections of a door bell.

6. MULTIMETER WHY MULTIMETER?
The most common electrical test equipment is a meter which is known as Multimeter.
WHY MULTIMETER?
Because it has the ability to measure different quantities such as voltage, current, resistance, and often many others.

7. MEASURING THE DC VOLTAGE OF A BATTERY

8. MEASURING THE AC VOLTAGE

9. CURRENT MEASUREMENT

10. CURRENT MEASUREMENT

11. CURRENT MEASUREMENT

12. SHORT CIRCUIT

13. When switching a multimeter from voltage- to current measuring mode
SHORT CIRCUIT
When switching a multimeter from voltage- to current measuring mode

14. HOW TO TEST A FUSE ?
A good fuse will indicate very little resistance

15. BLOWN FUSE

16. HAND-TO-HAND SHOCK
Hand-to-hand shock current path is the most dangerous, holding the meter probes on two points in a high-voltage circuit in this manner is always a potential hazard.
If the protective insulation on the probes is cracked then what will happen?

17. SAFETY CONSIDERATIONS FOR LIVE MEASUREMENT
Use only one hand.
Special probe tip accessories such as spring clips, crocodile clips can be attached.
Crocodile Clips
Spring Clips

18. DOOR BELL
The first doorbell was mechanical, activated by pulling a cord.
The transformer is used to step the voltage down from 220V to 16, 18 or 24 volts.
Modern doorbells are electric. They are actuated by an electric switch.

19. Electronic Door Bell

20. Electromechanical Doorbell

21. AC Doorbell

22. AC Power plugs and Scokets
AC power plugs and sockets are devices that allow electrically operated equipment to be connected to the primary alternating current (AC) power supply in a building.
Electrical plugs and sockets differ in voltage and current rating, shape, size and type of connectors.
The types used in each country are set by national standards, some of which are listed in the IEC technical report TR 60083, Plugs and socket-outlets for domestic and similar general use standardized in member countries of IEC.

23. AC Socket

24. AC Plug

25. Types of Sockets

27. Pakistan C, D, G, M 230V 50 Hz

31. AC Tester
Tester is used to test for live wire.

32. Practical Procedure
Current of Door Bell ?

33. THE END