Lesson Notes By Weeks and Term v4 - SHS 3
ELECTRONIC COMPONENTS AND CIRCUITS
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ELECTRONIC COMPONENTS AND CIRCUITS
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Subject: Applied Technology
Class: SHS 3
Term: 2nd Term
Week: 14
Grade code: 2.5.2.LI.3
Strand code: 4
Sub-strand code: 2
Content standard code: 2.5.2.CS.1
Indicator code: 2.5.2.LI.3
Theme: ELECTRICAL AND ELECTRONIC TECHNOLOGY
Subtheme: ELECTRONIC COMPONENTS AND CIRCUITS
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Welcome, future engineers and technicians! Today, we are diving into the world of Integrated Circuits (ICs), focusing on a very powerful and versatile component called the Operational Amplifier, or "Op-Amp". You have seen these small black components with many legs on circuit boards of radios, sound systems, and televisions. They look like tiny electronic spiders, but they are the brains behind many electronic functions. Understanding op-amps is crucial because they are used to amplify small signals, filter out noise, and perform mathematical operations in circuits.
2.1 What is an Operational Amplifier (Op-Amp)? An Operational Amplifier is a high-gain, direct-coupled (DC) differential amplifier. Let's break this down: High-gain: It can amplify a very small input signal to a very large output signal. The gain can be in the hundreds of thousands. Direct-coupled (DC): It can amplify both DC and AC signals. Differential Amplifier: It amplifies the *difference* in voltage between its two input terminals.
Op-amps are the fundamental building blocks of analogue electronics. They are found inside small black plastic or ceramic packages called Integrated Circuits (ICs). 2.2 The Op-Amp Symbol Before we look at the physical IC, we must know its electronic symbol. Inverting Input (-): Any signal applied here will be inverted (flipped 180°) at the output. Non-inverting Input (+): Any signal applied here will appear at the output with the same polarity (in-phase). Output (Vout): The output terminal of the amplifier. Positive Power Supply (+Vcc or +Vs): The positive voltage needed to power the op-amp. Negative Power Supply (-Vee or -Vs): The negative voltage needed. This is why it's called a dual or split power supply. 2.3 Pin Connections (Pinout) of Common Op-Amps
ICs have a standard way of numbering their pins. To find Pin 1, look for a small notch or dot at one end of the IC. With the notch/dot to your left, Pin 1 is the first pin on the bottom left. The numbering goes counter-clockwise.
a) The µA741 Op-Amp (A single op-amp IC) The 741 is one of the most famous and widely used op-amps. It contains one op-amp in an 8-pin package. Block Diagram / Pinout: Pin Functions: Pin 1 & 5 (Offset Null): Used to correct for small DC offset errors. For most simple circuits, we leave these unconnected. Pin 2 (Inverting Input): The inverting (-) input terminal. Pin 3 (Non-inverting Input): The non-inverting (+) input terminal. Pin 4 (-Vee): Connects to the negative power supply (e.g., -15V). Pin 6 (Output): The output terminal. Pin 7 (+Vcc): Connects to the positive power supply (e.g., +15V). Pin 8 (NC): Not Connected. It has no internal connection.