Multi-Way Switch Circuit

Multi-way switching is the most common method to be found in the electrical system. It provides user the comfort to turn ON and OFF any electrical appliances from more than one place. The most common use of multi-way switching is for lighting systems and placed in the most common areas of a building like hallways, reception area, kitchen, living room and many other. Multiway Switch Circuit can be easily made by using simple wires but here we are using IC CD4042. This IC can be latched at four outputs by giving the clock pulse, so we will control an AC light with four different buttons at four different places.

 

Material Required

• CD4042 IC
• NE555 timer IC
• Bulb or CFL
• Resistor (1k-2; 10k-2)
• Capacitor (0.1uf-2)
• 12v Relay driver module
• Switches- 4
• 12v supply

 

Circuit Diagram of Multi-way Switch

 

CD4042 Quad flip-flop IC

CD4042 has four flip-flop inside it, each strobe by a common clock. It has four data input and each data input has two outputs. The supply voltage of the IC is up to 18v (max.) and DC input current is up to ±10mA. The operating temperature of the IC is -55℃ to 125℃. The information available at the data input is transferred to outputs Q and Q’ based on the clock and polarity input.

The logic diagram and truth table of the IC is given below:

Clock	Polarity	Q
0	0	Input at pin D ( 0 or 1)
High pulse	0	Latch
1	1	Input at pin D ( 0 or 1)
Low pulse	1	Latch

 

You can understand the concept of using the polarity by the waveform below:

If the polarity set to Low or zero, by giving high to input, the output waveform will rise when the clock pulse get rise.

 

If the polarity set to high or one, by giving high to input, the output waveform will rise when the clock pulse falls.

 

Pin Diagram of CD4042 Quad flip-flop IC

  

 

Pin configuration of CD4042 Quad flip-flop IC

Pin No.	Pin Name	Description
1	Q4	Output of D4
2	Q1	Output of D1
3	Q1’	Inverting Output of D4
4	D1	Data input of flip flop 1
5	Clock	Clock input of the IC
6	Polarity	Set to change the rise time of the Output
7	D2	Data input of flip flop 2
8	Vss	Ground Pin
9	Q2’	Inverting Output of D2
10	Q2	Output of D2
11	Q3	Output of D3
12	Q3’	Inverting Output of D3
13	D3	Data input of flip flop 3
14	D4	Data input of flip flop 4
15	Q4’	Inverting Output of D4
16	Vdd	Positive supply pin

 

Working of Multi-way Switch

There are many ways to perform Multi-way Switching. Here, in this circuit we are using a CD4042 Quad flip flop IC. We are using NE555 timer IC in astable mode to feed the clock input terminal of the CD4042 IC. The flip flop inside the CD4042 IC works as per the table given below:

D	C	Q	Q’
0	Pulse	0	1
1	pulse	1	0

There are four Data pins (D0, D1, D2, D3), four output pins (Q0, Q1, Q2, Q3) and four inverting output pins (Q0’, Q1’, Q2’, Q3’). From these we are using data pin D0 and its output pins Q0 and Q0’, simply we are using only one flip flop of the IC.

Whenever the logic is provided to the Data pin D0 by any of the four switches, it gives output HIGH on Q0 and LOW on Q0’. Then a Relay module is attached to the Q0 output pin 2. As the relay triggered the bulb or light turns ON and remain in ON state until the switch is released. You can turn ON the light why pressing any of the four switches, which are set on different location in real. The light will turn OFF by releasing the same switch pressed for turning ON the bulb.

Instead of using Push Button in the circuit you can use Push On and OFF button to latch the output in a particular state.