Page 939 - Basic Electrical Engineering

Figure 13.17 Schematic diagram of a light and fan circuit

Example 13.4 Draw the schematic diagram for one lamp to be switched on
and off from any of the three positions.

Solution:

In this case we need to use a two two-way switch and an intermediate switch.
S and S are the two-way switches and S is an intermediate switch. The
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working of the single-way, two-way and intermediate switches have been
shown in Fig. 13.18 (a), (b), and (c). These have been used to make the

circuit as shown in Fig. 13.18 (d).

Figure 13.18 (a) One-way switch; (b) two-way switch; (c) intermediate switch; (d) schematic
diagram for a lamp controlled from any of the three positions

13.10 CIRCUIT PROTECTIVE DEVICES AND SAFETY PRECAUTIONS