Class notes
Electrical Engineering Semester 2 notes
- Institution
- University Of Cape Town (UCT)
This document includes all the lecture notes from the whole semester.
[Show more]
Seller
Follow
Content preview
W2 Electronic FundamentalsWhy Analogue Electronics?
- electronic systems with a continuously varying signal (in contrast to digital
electronics where signals usually take two levels (discrete)
- ‘analogue’ describes proportional relationship between signal and a
voltage or current that represents the signal
- an understanding of analogue electronics is important and essential when
designing an electronic interface to the physical world (e.g., an
analogue-to-digital converter (ADC)
- some technologies develop rapidly such as wireless communications
technologies
- many rapid advances have been enabled through the refinement of
semiconductors allowing billions of transistors to occupy single ICs
Resistors
Resistors are devices that obey Ohms law: V=IR
,Resistance:
Resistors come in standard values called the E12 and E24 series. The E12
series consists of multiples of the following values: 1, 1.2, 1.5, 1.8, 2.2, 2.7,
3.3, 3.9, 4.7, 5.6, 6.8, 8.2.
Tolerance:
The maximum deviation of the value of the resistor from its specified
value. Commonly available in 1% and 5% tolerances.
Power Dissipation:
Through-hole resistors are commonly available in power ratings of
0.25W, 0.5 W, 1 W, 2 W and 5 W. Most resistors can operate above 100
degrees C, meaning they can burn through breadboards.
Temperature Coefficient:
Any conductor’s resistance will change as its temperature changes.
This is called the Temperature Coefficient of Resistance (TCR) and is
different for different types of resistors.
Maximum Current:
Power dissipation is one factor which limits the maximum current, but
not the only factor. Short bursts of very high current can lead to a
resistor failing.
Maximum Voltage:
If the voltage placed across a resistor is too high there is a possibility
that it will spark across the resistor, or across one of the etched gaps in
the resistive film.
,Resistor Parasitics
▪ All resistors suffer from parasitic capacitance between parallel conductors,
and parasitic inductance. Some resistors are better than others.
▪ Normal through hole resistors are spirals of film around a ceramic rod, and
this give relatively high inductance.
▪ At radio frequencies (RF) the physical size of the resistor becomes
important, with physically smaller resistors typically giving more ideal
performance.
Reading a
Resistor
Through-hole
- Typically come with their values
indicated through the use of colour
bands
- There are either 4 or 5 bands
- Typically the tolerance band is on the
raised portion while the value bands
are in the middle
, Surface Mount (SMD)
- SMD or surface mount (device)
resistors do not have colour
bands, instead they have
numbers printed directly onto
them.
- The standard 3 and 4 digit code
does not give us a way to
determine the SMD resistor’s
tolerance.
- In most cases, however, SMD
resistors marked with a 3-digit
code has a tolerance of 5%,
one with a 4-digit code has a tolerance of 1%.
Potentiometers
- adjustable resistor dividers
Internally they have a resistive
track and a “wiper” that moves
along the track as the
potentiometer is adjusted.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller belenmorum. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R170,00. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
73096 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy summaries for 15 years now