This document provides an overview of relays, 555 timers, and operational amplifiers. It defines each component and identifies their basic functions and applications. Relays are electromagnetic switches that control electrical current using a small input signal. 555 timers produce oscillating outputs that can be used for timing functions. Operational amplifiers are integrated circuits that amplify signals and can be used as comparators by comparing inputs. The document includes diagrams of each component and examples of their uses.

1. Section 6: Relay,555timer & op-
amp
Creative Design & Innovation

2. Overview
This section will give you the skills needed to
understand the basic functions and application
of :-
- Relay
- 555 timer.
- Operational amplifier

3. Identify the basic functions and uses of a Relay.
Identify the basic functions and uses of a 555
timer IC (integrated Circuit).
Identify the basic functions of an Op-amp and
calculate the gain.
1
2
3
Learning Outcomes

4. Relay
A relay is an electromagnetic switch that can be enabled
by a small electrical signal and controls a much larger
electrical current.
Integrated circuits are advanced circuits that contains
many electronic components such as, transistors, diodes,
resistors and capacitors, all fixed into a micro silicon chip.
IC
A quick change in the value of a signal, from the original
value to a higher or lower one, then going back to the
original value again.
Puls
e
Electrical
oscillation
A regular variation about a certain central point in
magnitude or position for current or voltage.

5. Electrical
oscillation
A regular variation about a certain central point in
magnitude or position for current or voltage.
Key Vocabulary
A quick change in the value of a signal, from the original
value to a higher or lower one, then going back to the
original value again.
Puls
e

6. 1
Identify the basic functions
and uses of a Relay.

7. Relay
A relay is an electromagnetic switch that can
be enabled by a small electrical signal. This
internal magnetic switch can control a much
larger electrical current.

8. How does a Relay work?
Every Relay has a sensing unit, which is the electrical
coil. The coil is powered by an AC or DC current.
Electromagnetic Relay
- Has an electromagnetic
coil.
- Has an armature.
- Has a moving spring and
contacts.
- This relay is supplied by a
DC current.

9. The way the Relay works is simple.
There are two main circuits in a relay system.
1- Control Circuit.
2- Load Circuit.
Some Relays have their switch contacts
open by default.
- Normally open (NO)
- Normally colsed (NC Relays).

10. Types of Relay
Electromagnet
ic Relays
Solid-state
Relays

11. Types of Relay
Solid-state Relays
- Has no coil
- Has no spring
- Has no mechanical contact
switch
- Made from semiconductor
materials
- Have switching respone
Electromagnetic Relay
- Has an electromagnetic coil.
- Has an armature.
- Has a moving spring and
contacts.
- This relay is supplied by a
DC current.

12. Activity
2.36

13. Relay applications
We use relays for all electrical safety and switching systems.

14. Activity
2.37

15. 2
Identify the basic functions of an
Op-amp and calculate the gain.

16. Operational amplifier
Amplifires are devices that take a weak signal as an
input and produce a much stronger signal as an
output.
Op-amp is a special kind of amplifier.
We use it in Stereos and medical cardiograph. (
which amplify the heart beat)

17. Operational amplifier
Op-amp are integrated circuits that combine many
transistors, resistors and capacitors into a small silicon
chip.

18. Operational amplifier+ PIC
An op-amp has two different inputs:
- The inverting input.
- The non-inverting input.
Signals going into
The inverting input will be:- The non-inverting input will
be:-
Amplified
Just amplified
Inverted (flipped)

19. Operational amplifier
One of the most common Op-amps is the LM741 Op-amp, it’s
identical in appearance to the 555 timer.

20. Operational amplifier circuit diagram

21. Activity
2.38

22. Operational amplifier Applications
Op-amp are often used as comparator to compare two inputs.
( The inverting input and non-inverting input)
A common comparator is the temperature controller or
thermostat on a central heating system to sense
temperature and an op_amp.

23. Operational amplifier Applications
The voltage at the non-inverting inputs is greater
than the voltage at the inverting input.
This means that the room temperature is less
than the set temperature, and the op-amp
switches on the heating system.

24. Activity
2.39

25. Activity
2.40
Page 189

26. Gain of an operation amplifier
Op-amp have a high voltage gain of around 100,00. Negative
feedback is used to control the gain of an op-amp as shown
below.
The gain of an op-amp with negative feedback is calculated
by:
The minus ‘-’ sign
shows that the output
will always be inverted
when compared to the
input.

27. Activity
2.41
Page 190

28. 3
Identify the basic functions and uses of
a 555 timer IC (integrated Circuit).

29. 555 timer
It is a single-chip version of a commonly used
circuit called a multivibrator.
For example:-
We can use a 555 timer
to make an LED blink
ON and OFF.
If we control the frequency,
we are indirectly controlling
the time, thus the name
‘timer’.
555 timers allow us to choose how frequently this blinking
should occur (frequency).

30. 555 timer
We can use 555 timer to produce an oscillated
output.It is used in variety of timers:-
- Pulse generator
- Oscillator application
It has three 5 KΩ
resistors, thus has
the name 555
timer.
The 555 timer IC contains a lot of:-
- Transistors
- Resistors
- Diodes

31. Do you have any question
Thank You