Testing for Continuity : You may have observed sometimes that when all the connections in the appliance as well as the plug are made properly the appliance may still not work. This may be due to an open circuit fault. As you know that electricity flows only in a closed circuit, whenever there is a break in a circuit says the metallic conductor in the cable may be broken or the contact is loose or lost, the current will not flow. Further, it may so happen that you have properly earthed the appliance yet it gives a shock. One must ensure that there is continuity in the connection made whether for earthing or otherwise. This can be accomplished with the help of a multimeter or you may construct a simple continuity testing device of your own. Such an instrument works on the basis of passing a small current through the earth circuit to light a torch bulb. We have given an activity in this course where you will learn how to make a continuity testing device. You will also learn to use the device to check continuity of wiring and effectiveness of earthing in an appliance.