Module 3
Activity 02 - Indirect control of a lamp using a pushbutton switch and a relay.
Objectives:
• Introduce the
• Introduce the
• Introduce the
Introduce the
NC).
students
students
students
students
to
to
to
to
the
the
the
the
use
use
use
use
of
of
of
of
lab equipment.
DC power supply.
the pushbutton switches (NO and NC). •
the relay and the associated contacts (NO and
Background:
The relay is an electromagnetically operated switch; it will be used to indirectly control
a 24V lamp through a pushbutton switch.
Required Components:
1- DC power supply
2- Indicator unit
3- Switch block
4- Relay block
Procedures:
1. Connect the circuit according to circuit
shown in Fig.1, so the relay is a normally
open.
Figure 1
2. Switch on /off the pushbutton switch and observe the lamp and also the LED
of the relay block. Explain what happens to the lamp?
The lamp is not energized and does not illuminate when the pushbutton is
released, and the lamp illuminates and it normally operates when pressed and
held the pushbutton, through Relay block(K1) and make switch(K1). And
through the break switch(K2) the connection only flows to relay block(K2)
when pushbutton is pressed and held, and when pushbutton released the
lamp glows and the connection does not flow to the relay block(K2).
3. Replace the pushbutton switch with a detent switch and
repeat the same steps. Explain what happens to lamp.
When the on button of detent switch is pressed with the
make switch(K1), the lamp illuminates. When it is off,
there is no lighting. When the on button of detent switch
is pressed with the break switch(K2), the lamp does not
illuminate. When it is off, the lamp illuminates.
4. Connect the circuit according to circuit shown in Fig.2, so the
relay is in a normally close mode.
5. Switch on/off the pushbutton switch and observe the lamp
and the LED of the relay block. Explain what happens to
lamp.
It normally operates when the pushbutton is released and the lamp
illuminates and when pressed and held the pushbutton, the lamp is not
energized through Relay block(K1) and make switch(K1). And through the
break switch(K2) the connection only flows to relay block(K2) when
pushbutton is released, and when pushbutton pressed and held the lamp
glows and the connection does not flow to the relay block(K2).
Figure 2
Conclusion
The switch is used to interrupts the flow in a circuit and the flow of connection
can be depending to the switches used and I think these circuits and switches
show where it can be used like in on/off operation of devices or machine,
emergency stop etc.