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e-learning in
Electronics
The Design Process
Lesson 1: Circuit Simulations
Lesson 2: Design Decisions
Crocodile clips + modular circuit design
Lesson 4: Building the Prototype
Modular circuit design
Lesson 3: Realising my Design
Crocodile clips
Breadboarding
Lesson 5: Manufacture
PCB design / Automatic manufacture
Lesson 1
Circuit Simulations
Crocodile clips
Objectives
Aim
Develop a students electronics design skills though e-learning.
Develop confidence and knowledge in the use of crocodile
clips.
Objectives
Construct simple circuits using crocodile clips.
Make informed decisions over the choice of switches used in
electronics circuits through practical experience of their operation.
Incorporate logic gates as a means of controlling decisions within
basic circuits.
Discover ways of monitoring circuit action using probes, on screen
messages and graphical images.
Investigate the action of Astable and Monostable clocks using the
prepared circuits in the package.
1. Navigation and Tutorial
HTML link to crocodile
clips
The Crocodile Tutorial
The 2 tutorials under Help provides an
effective route for investigating the
initial workings of crocodile physics.
Activity 1
Follow the Electronics tutorial. This will
provide you with the initial skills
required to investigate this package.
2. Switching
In order to provide a clean transition
from 0 to 1 in TTL logic circuits
switches should be pulled cleanly
between 0V and 5V. This is done using
a pull down resistor R of 470Ω
Activity 2 – Using JU1_switches
Set the circuit with a logic monitor on
the output, then investigate the action.
Extension:
The circuit you have made is
commonly known as a Pull Up switch.
Try designing a pull down switch.
Sketch solution opposite:-
3. Logic Gates
Activity 3: Investigate the operation of the AND gate using the components provided in JU1_And,
then replace the AND gate with the OR gate provided. Now try completing the truth table for the
OR gate below.
4. Output Displays – The LED array
An LED normally needs a forward
voltage drop of 2V and sufficient light
is emitted with 10mA. A resistor is
usually added to protect the LED from
damage.
Activity 4: Find the value of the
resistor needed to control the current
at 10mA when the supply voltage is
5V. (Use JU1_LED)
Extension:
Add an Ammeter in series with the
LED, Resistor and find the safe current
which turns on the LED.
Fill in Answer here =
Now retry this with a voltage of 9V as
shown opposite. What protective
resistor is needed in this case?
JU1_switches_NOT
JU1_And_gates
JU1_LEDs
5. Monostable v Astable Clocks
Monostable.
A trigger pulse produces a
single pulse of fixed duration.
Astable
This is a free running and
produces a continuous supply of
pulses at the output.
Creating my First Clock
Activity 5: Using the models – Examples – Electronics Examples – Oscillator 1
provided investigate the settings required to produce an Astable clock with a
frequency of 1Hz or period of 1s. You will need to alter the resistor that
starts as 22k. Use the pulse in the graph to monitor the output frequency.